PHRM 200

Major Neutrotransmitters

*Excitatory* -->Glutamate -->Acetylcholine *Inhibitory* -->GABA -->Glycine

Cannabis Affects on the Basil Ganglia

Mainly affects *automatic functions and time* 1. *Automatic Motor Activities* -->unconscious movements, basic posture -->these activities may either be increased or decreased by cannabis 2. *Sense of Time* -->*conscious awareness* of the passage of time also requires the activity of the hippocampus -->*both* of these areas of the brain are affected by cannabis -->under the influence of cannabis, the impression is that *external time must have slowed down*, while the internal experience continues at the same rate -->time spent at a boring talk seems to pass more slowly General anesthesia: conscious time flow seems *unbroken* from the moment of falling asleep to the moment of waking

Pharmacophore

Molecular framework that carries (phoros) the *essential features* responsible for a drug's (pharmacon) biological activity 1. Defines the *important groups* involved in binding 2. Defines the relative *positions* of the binding groups 2. Need to know active conformation 4. Important to drug design and discovery

THC Derivatives

DMHP, HU-210, Nabilone, BIA 10-2474

THC Isomers (Schedule I)

*All* 7 isomers (delta 6a/7, 6a/10a, 7, 8, 9/11, 9, and 10) are listed as Schedule I narcotics

Serotonin Antagonist (Vomiting)

*Current treatment* for severe nausea and vomiting -Serotonin subtype *5-HT3* receptors: -->Ligand-operated cation channel (excitatory) -->Brain (excitatory), peripheral nerves (vagal-induced vomiting) -Ondansetron (*Zofran*™) is a *5-HT3 receptor antagonist*. Acts on receptors in upper *GI tract and CTZ* in the CNS. Very effective antiemetic. -Uses: 1. prophylaxis of chemotherapy and radiation induced nausea and vomiting 2. post-operative nausea and vomiting

Pain Perception: Physical Responses

*Somatic* Nervous System (*voluntary* movements) -->Skeletal Muscle-movement *Autonomic* Nervous System (*non-voluntary* movements) -->Smooth Muscle-blood vessels, lungs, GI -->Cardiac Muscle-heart rate -->Glands-hormonal signals (insulin, opioids, glucocorticoids etc.)

The Development of Neuropathic Pain

*Symptoms* are dependent on the *original source of pain* and the individual pathophysiology (including genetic and environmental influences)

Pain

-An *unpleasant* sensation that can range from mild, localized discomfort to agony -Pain has both *physical and emotional components* -Perceived pain does *not* always match the detectable source

Central and Peripheral Regulation of Nausea and Vomiting

-*CTZ* (chemoreceptor trigger zone) -->just outside the CNS -*Vomiting Center* -->in medulla

GABA-a Receptor

-*Chloride* Ion Channel Receptor (GABAA) -Most abundant *inhibitory* receptor in the brain -Opposes action of the Glutamate receptor -->*IPSP* -Important for anxiety, sleep, and drug addiction -Activated by: Anticonvulsants, Anxiolytics, Barbiturates, Hypnotics, General Anesthetics

Undesired Effects of NSAIDS

-*Gastrointestinal toxicity*: dyspepsia, bleeding, ulceration, perforation. -Bleeding: *platelet inhibition* -Renal toxicity: inhibition of intrinsic PG system -*Hepatotoxicity* -Hypersensitivity reactions

Glutamate Receptors

-*Ionotropic* Glutamate Receptors lead to *opening of Na+ channels*--EPSP -*Metabotropic* Glutamate Receptors activate G-protein coupled receptor that leads to activation of phospholipase C *(PLC)* and intracellular *Ca2+ release* -->continued activation of PLC leads to the formation of the endogenous cannabinoids *anandamide and 2-AG*

Other Activities that can Reduce Frontal Cortex Activity

-*Meditation* -Intense *exercise* induces transient hypofrontal activity -->the Runner's High: happiness, elation, feelings of unity with one's self and/or nature, endless peacefulness, timelessness, inner harmony -->*reduction of pain* sensations -*Daydreaming*

Transmission: Afferent Conduction

-*Nociceptors* -*Dorsal horn* of the spinal cord -Processed in the *thalamus*

Withdrawal and Cravings

-*Remodeling* of receptor expression leads to drug use as a means to *counteract the dysphoria and distress* associated with drug withdrawal and discontinuation -->drug is no longer sought for its stimulation of "High" but for its *relief of feeling sick* -Cannabis has the potential for producing a *psychological craving*, but it has a relatively *mild withdrawal* which reduces these effects

CBD Demand

-*Selective breeding* by growers in the USA dramatically lowered the CBD content of cannabis; their customers preferred varietals that were more *mind-altering* due to a higher THC, lower CBD content. -To meet the demands of medical cannabis patients, growers are currently developing more *CBD-rich strains*

Serotonin Pharmacology Note

-*Subtype-specific actions are important!* -Different subtypes are involved in anti-nausea, anti-psychotics, anxiolytics, anti-migraines, anti-depressants, etc.

Dimethylheptylpyran (DMHP)

-*Synthetic analogue* of THC, which was synthesized in 1949 during attempts to elucidate the structure of Δ9-THC -It produces similar activity to THC, such as sedative effects, but is *considerably more potent*, especially having much stronger analgesic and anticonvulsant effects than THC, although comparatively *weaker psychological effects* -->it is thought to act as a *CB1 agonist*, in a similar manner to other cannabinoid derivatives

HU-210 (1,1-dimethylheptyl-11-hydroxytetrahydrocannabinol)

-*Synthetic cannabinoid* (Agonist) first synthesized by Raphael Mechoulam that is *100-800 times more potent* than natural THC from cannabis and has an *extended duration of action* -The abbreviation "HU" stands for *Hebrew University* *(+)-enantiomer* of HU-210 has all of the cannabinoid activity, with the *(-)*-enantiomer HU-211 being *inactive* as a cannabinoid Effects: 1. potent analgesic with many of the same effects as natural THC 2. promotes proliferation of neural stem cells 3. may prevent the inflammation caused by amyloid beta proteins involved in Alzheimer's disease

Dronabinol (Marinol)

-*Synthetic* delta-9-THC -US FDA approved for nausea due to cancer chemotherapy in 1986 -->marketed by Abbvie -Approved for HIV-AIDS associated weight loss -Marinol is an FDA *approved* Schedule III drug, although Dronabinol (THC) is Schedule I (no medicinal use) -Patients do not tolerate as well as cannabis -->*entourage effect*

Recreational/Medical Use Correlation

-76% of those who reported having a physician recommendation also reported recreational use -*Acceptance of Recreational Use Increases Medical Use*

Dravet Syndrome and CBD

-A number of high profile and anecdotal reports have sparked interest in treatment of Dravet snydrome with CBD -->Dravet syndrome is a *rare form of epilepsy* that is difficult to treat -->it is a catastrophic form of intractable epilepsy that begins in infancy -GW Pharmaceuticals is seeking FDA approval to market a formulation of CBD, under the trade-name *Epidiolex*, as a treatment for Dravet syndrome (was granted fast-track status and completed an NDA)

Adolescent Vulnerability to Cannabis

-A significant effect on *IQ* was only seen in users that were dependent *before age 18* Why? -Age 13-18 is a period of *critical brain development* -->neuronal maturation and rearrangement processes -->maturation of neurotransmitter systems -->*vulnerable* to toxic insult -*Adolescents* have shown structural and functional brain differences associated with cannabis use. -->*NOT* because they receive less education

Common Properties of Addicting Drugs

-Affect the *Reward Pathway* -->stimulate dopamine signaling in the Reward Pathway, *rapid* activation -->*withdrawal* of drug *inhibits* the Reward Pathway -Produce conditioned place preference behavior in animal models -Voluntarily administered (specifically to the reward center in animal models) -Trigger *relapse* to drug-seeking behavior -Cannabis *produces all these effects* (including conditioned place preference and voluntary administration) to some degree -->THC -->But....*CBD opposes them*

Partial Agonist

-Agents which act as agonists but produce a *weaker* effect -Same potency, *lower efficacy* Possible explanations: 1. Agent binds but does not produce the ideal *induced fit* for maximum effect. 2. Agent binds to binding site in *two different modes*, one where the agent acts as an agonist and one where it acts as an antagonist 3. Agent binds as an agonist to one receptor subtype, but as an antagonist to another receptor subtype

2-AG

-Also another *endogenous ligand* of CB1/CB2 -Anandamide and 2-AG are both derived from Arachidonic Acid

Anandamide Signaling

-Anandamide functions as a *retrograde signaling molecule* that modulates release of anterograde transmitters -CB1 activation mediated *activation* of K+ channels or *inhibition* of Ca2+ channels.

Anandamide (AEA)

-Anandamide, also known as N-arachidonoylethanolamine, is an essential *fatty acid neurotransmitter* derived from the non-oxidative metabolism of arachidonic acid -The name is taken from the Sanskrit word ananda, which means *"joy, bliss, delight"*, and amide -AEA is degraded primarily by the fatty acid amide hydrolase (*FAAH*) enzyme, which converts it into ethanolamine and arachidonic acid -*Endogenous ligand of CB1/CB2*

Antagonists

-Antagonists have *affinity, but no efficacy* for their receptors, and binding will disrupt the interaction and inhibit the function of an agonist -The majority of drug antagonists achieve their potency by *competing* with endogenous ligands or substrates at structurally defined binding sites on receptors

Cannabis in Combatting Addiction

-Antagonists to the CBR1 receptors decrease addiction behavior towards ethanol, nicotine, opiates, and stimulants -Blockade of CB1Rs specifically in the VTA decreases alcohol and nicotine self-administration, and blockade of CB1Rs specifically in the NA reduces alcohol consumption -->could some strains of cannabis be used to substitute for more addicting drugs as a means of drug treatment? *Cannabis down-regulates their receptors to a certain effect, which reduces illicit drug effects on the receptors*

Arachidonic Acid

-Arachidonic acid is a *polyunsaturated fatty acid* present in the phospholipids of *membranes* and is abundant in the brain, muscles, and liver. -*Skeletal muscle* is an especially active site of arachidonic acid retention, accounting for roughly 10-20% of the phospholipid fatty acid content on average -In addition to being involved in cellular signaling as a *lipid second messenger* involved in the regulation of signaling enzymes, such as PLC-γ, PLC-δ, and PKC-α, -β, and -γ isoforms, arachidonic acid is a key *inflammatory intermediate* and can also act as a *vasodilator*

Location of Cannabis Receptors (Low Toxicity)

-CB1 and CB2 receptors are *not* expressed at significant levels in the *lower brain stem* (medulla and pons) -->opioids and ethanol depress the chemoreceptor activity in the medulla, thus breathing slows even in hypoxia -Opioids and ethanol also increase vomiting risk, death due to *aspiration*

CB1 Receptors and Dopamine Signaling

-CB1 receptors affect signaling to dopamine receptors in the reward pathway -*Endogenous* cannabinoids are only produced when the dopamine neuron is *hyper-stimulated*, to turn off the signals -*Reduces suppression* of the reward pathway through the *inhibition of GABA*

Cannabigerol (CGB) & Cannabichromene (CBC)

-CBG and CBC are both *non-psychoactive* natural cannabinoids -CBG is found in *higher concentrations in hemp* rather than in varieties of Cannabis cultivated for high THC -->CBG as been shown to relieve intra-ocular pressure, which may be of benefit in the treatment of *glaucoma*

CBN Scheduling

-CBN is *not* scheduled by the United Nations' Convention on Psychotropic Substances -Although CBN is not scheduled at the federal level in the U.S., it could legally be considered an *analog of THC* and sales or possession could be prosecuted under the Federal Analogue Act

Cannabidiol (CBD)

-Cannabidiol (CBD) is a major phytocannabinoid, accounting for up to *40%* of the plant's extract -CBD is believed to have a wider scope of potential medical applications than THC -Cannabis produces *CBD-carboxylic acid* through the same metabolic pathway as THC (i.e. CBGA), until the last step, where *CBDA synthase* performs catalysis instead of THCA synthase

Cannabinoid vs. Opioid Receptors (Location)

-Cannabinoid Receptors reside in the *same* locations as opioid receptors in pain pathways --at the tissue pain source -->in the transduction pathway -->in the descending modulatory pathways -Some discrepancy over their effects on glutamate vs. glycine or GABA with respect to pain -Endogenous cannabinoids may have a different role than THC

Cannabinoid Agonist Efficacy with Pain

-Cannabinoid agonists are effective in *all peripheral neuropathic pain models* -*Nerve Injury* -->Sciatic nerve ligation (SNL and PSNL) -->Sciatic nerve injury (CCI, SNI) -Diabetes -->Streptozotocin -Chemotherapy -->Paclitaxel, Cisplatin -HIV neuropathy

Cannabinol (CBN)

-Cannabinol (CBN) is a *weak psychoactive* cannabinoid found only in trace amounts in Cannabis sativa -CBN is mostly a *metabolite* of tetrahydrocannabinol (THC) -->unlike other cannabinoids, CBN does not stem from CBG, but is the *degraded product* of THC -CBN acts as a weak agonist of CB1 receptors, but has a *higher affinity* to *CB2* receptors -->if cannabis is exposed to air or ultraviolet light for a prolonged period of time, THCA will convert to *CBNA* -->CBN is then formed by *decarboxylation* of CBNA -In contrast to THC, CBN has *no double bond isomers nor stereoisomers*

Cannabis vs. Opioids (Pain Efficacy)

-Cannabis has been shown to be *very effective* in the treatment of pain -*Not* likely to be as effective as opioids, but have *synergistic actions*, thus *lower dose* of opioid can be used -May be achieved by *both THC and CBD* -->more research needed to determine why and what combination is best

Cannabis Hyperemesis Syndrome

-Chronic cannabis use -Cyclic episodes of *nausea and vomiting* -Frequent *hot bathing*—seems to alleviate symptoms -Hyperemetic phase usually ceases within 48 hours, and treatment involves supportive therapy with fluid replacement and anti-emetic medications -->abstaining from cannabis use is the *best therapy*

Cannabis and Schizophrenia

-Conflicting data -Strong association data, especially in early onset chronic use -->poor cause-effect data -Genetic analysis found an association between an individual's burden of schizophrenia risk alleles and use of cannabis -->thus early schizophrenia symptoms may lead patients to *self-medicate* with cannabis

Cannabis and Depression

-Conflicting data -Strongest support for a link to *major depressive disorder* and *bi-polar disorder* with chronic use or addiction -->also a link if co-dependent on alcohol -No significant link between depression and occasional use in adults -Some studies showing *moderate* use has *antidepressant effects*

The Reward Pathway

-Connects *limbic regions* of the brain -->VTA-ventral tegmental area -->NA-nucleus accumbens -->FC-frontal cortex -*Dopamine* receptor signaling tracts -Overactivity is linked to *psychologic addiction*

Modulation: Efferent Conduction

-Descending Inhibition -*Periaqueductal gray* area in the midbrain -*Rostral ventral medulla*

THCA Decarboxylation In Vivo

-Despite the ready decarboxylation by drying or heating ex vivo, conversion of THCA to THC in vivo appears to be *very limited*, giving it only very slight efficacy as a *prodrug* for THC -For that reason, THCA is believed to be important in *less-psychoactive preparations* of cannabis used for medical use, such as cannabis tea

BIA 10-2474

-Developed by the Portuguese pharma company Bial-Portela & Ca -Long-acting *inhibitor* of fatty acid amide hydrolase *(FAAH)* that *increases* levels of the neurotransmitter *anandamide* in the central nervous system and in peripheral tissues -FAAH inhibitors have been proposed for a range of nervous system disorders including anxiety disorders, alcoholism, pain and nausea -A clinical trial with this drug was underway in Rennes, France, in January 2016, in which *serious adverse events occurred* affecting five participants, including the death of one man

Side-effects of 5-HT3 Inhibitor

-Diarrhea -Headache -Fever -Lightheadedness -Dizziness, drowsiness -Constipation -Rash -Blurred vision -Muscle spasm *Not completely effective* for chemotherapy-induced vomiting

Daydreaming

-Directed sustained attention requires *Frontal Cortex functioning* -*Automatic motor activities* are controlled by the *Basal Ganglia* -The frontal cortex is relatively inactive during daydreaming (similar to REM sleep) -While daydreaming, humans are capable of an astonishingly high level of processing -->ex: driving a familiar route

Enjoyable Cannabis Experiences

-Dizziness or lightheadedness -Relaxed calm and a feeling of being "disconnected" -Altered Perceptions -->awareness of the senses and of music may be increased -Distorted sense of time -Slowed reaction time -Decreased attention, sedation -Giggles and euphoria -Appetite increases

Retrograde Signaling (CB1)

-Endocannabinoid signaling induces *synaptic depression at excitatory synapses* -"Process by which a retrograde messenger, such as anandamide, is released by a *post*synaptic dendrite or cell body, and travels *"backwards"* across a chemical synapse to bind to the axon terminal of a *pre*synaptic neuron"

Opioids (Steps 2-4)

-Examples: morphine, hydrocodone (Vicodin), oxycontin, Percocet, fentanyl -Agonist for the mu opioid receptor -->*inhibits neuron activity* -->coupled to *Gi* -->inhibits Ca2+ entry, increase K+ exit, reduce cAMP -->excess stimulation causes receptor *down-regulation* and changes in gene expression-*tolerance*

FAAH Inhibitors

-FAAH degrades anandamide and other endocannabinoid neurotransmitters -FAAH inhibitors such as URB-597 and LY-2183240 have been sold illicitly as designer drugs -Other pharmaceutical companies, including Merck, Pfizer, Johnson & Johnson, Sanofi and Vernalis, have previously taken other FAAH inhibitors into clinical trials *without experiencing such adverse events* -->have all halted their trials however

Fast Dopamine Release

-Fast arrival to the brain and fast dopamine release are necessary to initiate reward -->injection/inhalation vs. oral administration -THC rapidly enters the brain due to its *lipophilicity*

Brain Regions Effected by Cannabis

-Frontal Cortex -Basal Ganglia -Amygdala -Hippocampus -Hypothalamus Note: *Not* highly expressed in the brain stem--medulla that regulates breathing

Therapeutic Use of Cannabis

-Genetic mutations in the ion channels contribute to the development of *Epilepsy* -Basal Ganglia is damaged in *Parkinsons* -Hippocampus and Frontal Cortex are damaged in *Alzheimer's* -Hypothalamus is dysfunctional in *eating disorders*

THC Biosynthesis

-Geranyl pyrophosphate (GPP) and olivetolic acid react, catalyzed by a hemp transferase to produce cannabigerolic acid (CBGA), which is cyclized by the enzyme THCA synthase to produce THCA -THCA is then decarboxylated to form THC -->decarboxylation is *not* part of the biosynthetic pathway but occurs *spontaneously*

CBD Current Research

-Has been shown to be an *anticonvulsant* in animals -Nabiximols (USAN, trade name *Sativex*) is an aerosolized mist for oral administration containing a near 1:1 ratio of CBD and THC -->the drug was approved in Canada in 2005 in the UK in 2010 to *alleviate pain* associated with multiple sclerosis, *neuropathic pain*, spasticity, and overactive bladder syndrome

The Dunedin Study (Longitudinal Population Study)

-Health, development and well-being of a general sample of 1,037 New Zealanders. -They were studied at birth (1972-73), followed up and assessed at the age of three when the longitudinal study was established. -Since then they have been assessed every two years until the age of 15, then at ages 18 (1990-91), 21 (1993-94), 26 (1998-99), 32 (2003-2005), and 38 (2010-2012). -Data obtained on *Physical health, Mental Health, and Socialization*—a tremendous amount of data -Over 2,000 publications have used these data

Opioid Abuse

-Heroin: more abuse potential than other opioids -->high *lipid solubility* -->converted to morphine -Oxycontin: Extended release oxycodone Therapy: Methadone, Buprenorphine (*agonist and partial agonist*) -->less euphoria, oral, long acting, helpful in psychological addiction

CB1 Receptors in the Reward Pathway

-High density of CB1 receptors in the *VTA* -CB1 receptors *less abundant* on the dopamine neurons -CB1 receptors are found on *GABA neurons* -->reward due to *inhibition of GABA* (similar to opioids)

Immune Contribution to Neuropathic Pain

-Immune cells at the pain source can *sensitize* primary nociceptors -Immune cells in the spinal cord can sensitize secondary nociceptive neurons -Results in *pain hypersensitivity*

Geranyl Pyrsphosphate Synthesis

-Isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) are condensed by geranyl pyrophosphate synthase (dimethylallyltranstransferase) to produce geranyl pyrophosphate (GPP) and pyrophosphate -Geranyl pyrophosphate (GPP) is an *intermediate* in the HMG-CoA reductase pathway in the biosynthesis of *cholesterol, terpenes and terpenoids*

Medical Cannabis Legalization and Opioids

-Legalization of medical cannabis correlates with *lower opioid overdose mortality rate* -->medical cannabis laws are associated with significantly *lower state-level* opioid overdose mortality rates -->using the period 1999-2010, states with medical cannabis laws had a *24.8%* lower mean annual opioid overdose mortality rate (P = .003) compared with states without medical cannabis laws

Glycine Receptors

-Like GABA, a *Chloride* ion channel -*Inhibitory* to Glutamate signals -Binding sites for glycine and the potent antagonist strychnine -Cannabinoids have been shown to *enhance Glycine receptor activity* -->this is a *separate activity* from their binding and activating the CB1 Receptors

Lipid Signaling

-Lipid signaling is defined as any biological signaling event involving a *lipid messenger* that binds a protein target, which in turn mediate the effects of these lipids on specific cellular responses -Lipids can freely *diffuse through membranes* -One consequence of this is that lipid messengers cannot be stored in vesicles prior to release and so are often *biosynthesized "on demand"* at their intended site of action -->cannot circulate freely in solution but, rather, exist *bound to special carrier proteins*

Glutamate Receptors (Pain)

-Metabotropic Glutamate Receptors activate G-protein coupled receptor that leads to activation of phospholipase C (PLC) and *intracellular Ca2+ release* -*Substance P* is a neuro-active peptide that is *co-released* with glutamate and also activates Ca2+ signals -->important element in *pain perception and inflammation*

Transient Negative Experiences on Cannabis

-Mild to severe anxiety, paranoia -Feeling tense or agitated -Confusion and memory loss -Clumsiness -Headache -Hangover -->dry mouth, dry eyes, fatigue, cognitive impairment, memory loss

Cannabis and the Hippocampus

-Modestly *inhibits* the hippocampus -Hippocampus is important in *learning & memory* -->for memory, hippocampus is responsible for *immediate recall, short-term memory, and retrieval*

Sensing Pain: Nociception

-Nociceptor -Transduction -Transmission -Modulation -Perception

Nociceptor Signaling

-Nociceptors signal to the *spinal cord* and also activate inflammation -Activated by multiple stimuli -->express multiple receptors -Neurons secrete *substance P* -Also stimulate immune cells and cause *vasodilation*

Opioids (General)

-Opiates are derived from Papaver somniferum (*poppy*) -Morphine, codeine, heroin -*Synthetic opioids*: methadone, fentanyl

Opioids: Dependence with Long-Term Use

-Opioid agonists stimulate *receptor desensitization* -->results in tolerance and potential for physical and psychological addiction -Tolerance and physical dependence is common in long-term pain therapy, but psychological dependence is rare -->patients may require higher doses to alleviate pain -->patients *do not* experience *euphoria* when suffering pain -*Psychologic dependence* is a serious problem when opioids are *abused* -Produces *physical withdrawal* -Intense craving that can recur long after recovery

Decarboxylation of THCA

-Over time, or in the presence of *heat or light*, THCA is decarboxylated to THC -Boiling point for THC is 157°C or 315°F

Similarities Between CB1/CB2

-Overall sequence similarity is *44%* -Considering only the transmembrane regions, the *amino acid* similarity between the two receptor subtypes is *68%*

Chronic Pain and Remodeling of Pain Pathways

-Pain *Sensitization* -Increases production of *substance P* -Increases the number of *nociceptor* fibers -Reduces the threshold for pain -Amplifies the *perceived pain*

"Executive" Functions of the Frontal Cortex

-Planning, organization and *execution of complex behavioral sequences* (Working Memory) -Flexible responses to changing environmental contingencies -->primarily active in response to *new experiences* -*Selective attention* -Persistence in a task despite distraction -*Creative* problem solving -Inhibition of automatic ("prepotent") responses ("cognitive control") -*Abstract* reasoning

Supercritical Fluid Extraction (SFE)

-Process of *separating* one component (the *extractant*) from another (*the matrix*) using supercritical fluids as the extracting solvent -Extraction is usually from a solid matrix, but can also be from liquids -Based on the principle that *solubility in a supercritical fluid increase dramatically with increasing density*, and *different solutes have different solubility at the same condition*

Reflex Responses

-Regulated by the *spinal cord* -Opposing muscle groups need to communicate -Contraction of one group requires stretch of the other -->bicep contraction requires tricep stretch -Coupled by inhibitory neurons in the spinal cord -Basic reflexes are stimulated by *stretching* the muscle -Does *NOT* require CNS input

Cannabis Addiction

-Relatively *uncommon* -Although THC can activate *CB1 receptors* in the Reward Pathway, the *receptor density is low* compared with the opioid receptor density -Among regular users (daily), the rate of clinical addiction is *~9%* -->this rate is higher for users who begin *under the age of 18* and are chronic users

Organ Systems Effected by Endocannabinoid System

-Virtually *all* of the body's systems are influenced by the endocannabinoid system -Deficiencies in the functioning of the ECS appear to be major causes of certain diseases -The ECS appears to play at least a minor role in basically *every aspect* of human health and sickness

Lipinski's Rule of 5

-Rule of thumb to evaluate *drug likeness* or determine if a chemical compound with a certain biological activity has properties that would make it a likely *orally active drug* in humans -The rule states that an orally active drug has *no more than one* violation of the following criteria: 1. No more than 5 H-bond donors 2. No more than 10 H-bond acceptors 3. A molecular mass less than 500 daltons 4. A log P not greater than 5

HU-210 Recreational Use

-Several *psychoactive artificial* cannabinoid families are found in designer drugs, *sprayed* on herbs and sold as "natural highs" (K2, Spice) -Research on the safety of synthetic cannabinoids has initially focused on their role in *psychosis* -->HU-210 and other synthetic cannabinoids may induce psychosis -*More toxic and addictive* than regular cannabis

Cannabis Euphoria & Laughter

-Spontaneous laughter has more to do with *social relationships* than humor -It is the brain's *frontal lobes* that make sense of the discrepancy between the script and the situation described by the joke or illustrated by the cartoon -->this ability is unique to our species -->to *"get"* a joke, you have to *coordinate multiple brain areas*: your initial assumptions, stored in the hippocampus, along with the alternative explanations that are worked out with the aid of the frontal lobes *Cannabis use increases the spontaneous forms of laughter that don't require forebrain functions*

Dopamine Secreting Neurons of the VTA

-Stimulate multiple brain regions: -->Frontal Cortex -->Hippocampus -->Amygdala

Cannabis and Lung Function

-Surprisingly, smoking marijuana was linked to *slightly improved* lung function -->users breathe *very deeply* which increases their lung capacity -->however, this only last a few years

Nabilone

-Synthetic cannabinoid which *mimics Δ9-THC* (Agonist) -Marketed as *Cesamet* -Although the FDA approved it 1985 for the *treatment of chemotherapy-induced nausea and vomiting*, the drug only began marketing in the U.S. in 2006 -Effective in the treatment of *movement disorders* such as parkinsons, dystonia and spasticity neurological disorders, and multiple sclerosis -->also used to treat inflammatory bowel disease, especially ulcerative colitis -Medical cannabis patients report that nabilone is *more similar to cannabidiol* (CBD)

THCA Scheduling

-THCA is *not* scheduled by the United Nations' Convention on Psychotropic Substances -->however, it is possible that THCA could legally be considered an analog of THC and sales or possession could potentially be prosecuted under the *Federal Analogue Act* -There is also a practical legal issue of potential THC contamination of THCA, which should be considered -->it is somewhat unlikely that any sample of THCA will not contain a quantifiable amount of THC

Tetrahydrocannabinolic acid (THCA)

-Tetrahydrocannabinolic acid (THCA, Δ9-THCA, 2-COOH-THC), is a biosynthetic *precursor* of THC, the active component of cannabis. -The purified form is a powder which is unstable in the presence of acids, heat, oxygen, and/or light -THCA is found in variable quantities in fresh, *undried* cannabis, but is progressively *decarboxylated* to THC with drying, and especially under intense heat such as smoking -Does not have any known psychoactive effects on humans, but it is shown to have anti-inflammatory, neuroprotective, anti-emetic, and can reduce oxidative stress -->it inhibits COX-1 and COX-2 enzymes involved in inflammation

Carbon Dioxide (CO2)

-The *most used supercritical fluid*, sometimes modified by co-solvents such as ethanol or methanol -Extraction conditions for pure supercritical carbon dioxide are above the critical temperature of 31C and critical pressure of 74bar (1073 psi)

Gut (CB1 and CB2 Receptors)

-The Gut contains *both* CB1 and CB2 Receptors -Secretion: CB1 -Motility: CB2 -Inflammation: CB1,CB2 -Neuronal hypersensitivity: CB1,CB2

Stroop Interference Effect

-The Stroop interference effect was *significantly greater following marijuana use* -Marijuana may compromise *associative control*, presumably a cognitive process inherent in memory function -Early onset chronic marijuana smokers demonstrate altered Stroop performance and brain activation

Proposed Pharmacophore of THC

-The proposed pharmacophore for THC includes the basic tricyclic benzopyran structure with a double bond at either Δ9- or Δ8-position in the alicyclic ring -Derivatives with a double bond in the 6a, 10a position (not found in nature) have pharmacological profiles similar to Δ9-THC -*Biological activity varies with the position of the alkyl substituent in the side chain at C-3* -->the 1',2'-dimethylheptyl-pyran (DMHP) derivative was 500-fold more potent than Δ9-THC See Desktop

Cannabis Cannabinoids

-The two cannabinoids usually produced in greatest abundance are *cannabidiol* (CBD) and/or *Δ9-tetrahydrocannabinol* (THC), but only THC is psychoactive -*Cannabinol* (CBN) is a *weak psychoactive* cannabinoid found only in trace amounts in Cannabis *sativa* -->it is mostly a *metabolite* of tetrahydrocannabinol (THC).

Tolerance to Cannabis

-Tolerance is seen for the THC-mediated *depressant effects* of cannabis with limited use -->less effect on motor coordination and sedation -Tolerance is seen for the THC-mediated *euphoric effects* with chronic use -Increased dose *does not* overcome this tolerance, thus *decreasing the incidence of dependence* -->the receptor number is low to begin with, so *down-regulation* limits the effect of increased dose *CBD also opposes some of the THC effects while having no antagonists that down-regulate its receptors* -->very little tolerance to effects of CBD

Synergistic Toxicities

-Unlike alcohol and opioids, there is very *little potential* for synergistic *CNS depression* with cannabis -Opioids, anxiolytics, sedatives, sleep-inducers, anti-seizure agents, and general aesthetics would all be *dangerous in combination*

Cannabis Lung Toxicity

-Unlike cigarettes, smoking cannabis has *not* been associated with *lung cancer*, but is associated with *chronic bronchitis* -->although there are carcinogens in the smoke, users simply *don't ingest as much* -->chronic use can lead to chronic bronchitis due to *particulates* in the smoke ----->persistent cough ----->exacerbated asthma or allergic response ------>longer recovery from respiratory infections -*Vaporizers* reduce contaminants, and *do not* have the same risks as nicotine vaping -->cannabinoids *easily vaporize* from the plant, thus avoiding the need for additional chemicals that may be toxic -->less risk of bronchitis

Worries of Long-Term Health Effects

-Worry about long-term effects on public health is the *biggest setback* for the legalization of medical cannabis -The findings related to cognitive effects have led to extreme caution in the legalization of both recreational and medical cannabis -Use is *limited* to those over the age of 21 -Medicinal use in patients under 18 is only for *extreme cases* of cancer pain or epilepsy

Neuron Communication

1. *Action potential* invades the nerve terminal; *depolarization* activates voltage-dependent calcium channels 2. Influx of *Ca2+* through Ca2+ channels 3. Transmitter (Excitatory or inhibitory) released into the cleft 4. Reaction of the transmitter with specific receptor sites 5. Activation of transmitter-gated channels initiates a synaptic current that leads to synaptic potentials -->Excitatory post-synaptic potential *(EPSP)* -->Inhibitory post-synaptic potential *(IPSP)*

Endogenous Opioid Peptides

1. *Endorphin*: hormone -->released by the pituitary gland and hypothalamus in response to *stress* -->part of pro-opiomelanocortin (POMC) -->bind μ receptors 2. *Enkephalin*: neurotransmitter -->produced in neurons, released in response to prolonged depolarization -->bind μ and δ receptors 3. *Endomorphin* -->bind μ receptors 4. *Dynorphin* -->bind κ receptors

Cannabis Effects on Attention and Memory

1. *Peripheral attention reduced* -->a person who is high may become absorbed in an object, event, or process to the exclusion of everything else 2. *Memory* -->both short-term and long-term memory impairment 3. *Color/Image Perception* -->hallucinogenic effects 4. *Motor Coordination* -->impaired, but much less than alcohol or opioids

Death by Overdose

1. *Stimulants*: Activate stimulatory neurotransmission -->Nicotine (Na+ channel) -->Amphetamine/Meth (Dopamine) -->Cocaine/Crack (Dopamine) -->Overdose: *Cardiac Arrhythmia* 2. *Depressants*: Activate inhibitory neurotransmission -->Alcohol (increase GABA, decrease Glu) -->Opioids (Opioid Receptors inhibit neurotransmission) -->Overdose: *respiratory suppression* 3. Hallucinogens -->LSD (Activates Specific Serotonin Receptors) -->PCP (Inhibits Glutamate Transmission) 4. Cannabis: A mixture of effects due to *inhibitory* activities at both *GABA and Glutamate neurons*

Side Effects of Opioids

1. Nausea -->Actions in *chemotrigger zone* of CNS -->Tolerance usually develops 2. Constipation/Vomiting -->Opioid receptors in gut *decrease motility* -->*No* tolerance 3. Itching -->Common due to *altered sensory signaling* -->Can be treated with antihistamine 4. Respiratory Suppression -->Not usually seen with continued use due to tolerance -->Reversed by Naloxone

Therapeutic Effects of NSAIDS on Pain

1.Analgesia -->Within an hour -->PGE2 *sensitization* of nociceptors 2. Antipyretic (lowers fever) -->Within an hour -->PGE2 in hypothalamus 3. Anti-inflammatory -->Within days (may take weeks for some conditions) -->PGE2-mediated edema and leukocyte recruitment There is a *limit* to the *maximum pain relief* given by NSAIDS (not effective for *neuropathic or cancer pain*)

Opioid Receptors in Pain Pathways

Afferent Conduction: -->Few at the site of injury -->Dense in the *dorsal horn* of the spinal cord -->Dense in the thalamus -->Opioids *Inhibit conduction* Efferent Conduction: -->Dense in the periaqueductal gray area in the midbrain -->Dense in the rostral ventral medulla -->Opioids *indirectly activate inhibitory conduction* Conclusion: 1. *Inhibit ascending pain transmission* 2. *Indirectly stimulate descending pain modulation*

Afferent Signaling

Afferent: Sending messages *to* the CNS -*Sensory* receptors -*Somatic*, Visceral or Spidey Peripheral NS-->CNS

Location of Cannabinoid Receptors in Pain Pathways

CB1 Receptors: -->High Density in the CNS -->Sensory Neurons (*afferents* going to the brain) -->Autonomic Nervous System (*efferents* that communicate with organs) CB2 Receptors: -->Highly expressed in immune-related organs -->Spinal Sensory Neurons (*afferents* going to the brain) -->Role in pain is thought to be mostly immune cell-mediated

CB1R and Vomiting

CB1 receptor activation *inhibits* the vomiting center

Binding Affinity of Cannabinoids to CB1/CB2

CB1: 1. Anandamide--32nM (agonist) 2. THC--41nM (partial agonist) 3. CBD--4350nM (antagonist) CB2: 1. Anandamide--1930nM (agonist) 2. THC--36nM (partial agonist) 3. CBD--2860nM (antagonist)

CB1/CB2 Signaling

CB1: *neuromodulation* between a sending and a receiving neuron. CB2: *immunomodulation* between sending neuron and receiving immune cell

Cannabinoid Receptors

CB1: expressed mainly in the *brain*, but also in the lungs, liver and kidneys CB2: expressed mainly in the *immune system* and in hematopoietic cells Both are *G-Protein coupled receptors*

Therapeutic Effects of Opioids

CNS effects: -->excellent *analgesia * -->*change in pain reaction* -->euphoria -->drowsiness -->*cough suppression* Peripheral effects: -->*Anti-diarrheal* (constipating) Opioids offer the *highest level of pain relief* other than nerve block or general anesthesia

Cannabis Effects on the Amygdala

Cannabis *increases/decreases* activity in the Amygdala -The natural endocannabinoid receptors in the amygdala regulate anxiety and the response to stress by *dampening excitatory signals* -Chronic stress or acute, severe emotional trauma can cause a *reduction* in both the *production* of endocannabinoids and the *responsiveness* of the receptors -->without their "buffering" effect, anxiety goes up -While "exogenous" cannabinoids also can reduce anxiety, *chronic use of the drug can paradoxically increase anxiety* -->this can trigger "a vicious cycle" of increasing marijuana use that in some cases leads to addiction

Cannabis and Frontal Cortex Suppression

Cannabis causes *temporary Frontal Cortex suppression* -Attraction to environmental stimuli -*Impairment of abstract reasoning* & problem solving -Automatic, concrete, stimulus-bound behavior -Loss of planning and sequencing of complex behavior -*"Frontal amnesia"*: spontaneous recall impaired, recognition intact

Cannabis and Hunger

Cannabis induces hunger primarily through effects on the *Hypothalamus* -There are *many cannabinoid CB1 receptors in the hypothalamus* -->CB1 receptor stimulation causes *release of endorphins* (endogenous opioid) by hypothalamic neurons -->these neurons normally signal feelings of fullness, but THC causes them to *stimulate hunger* (a very unusual pathway) -This pathway could be very important in future studies of appetite

Dunedin Study: Effects of Marijuana

Cannabis use was ascertained in interviews at ages 18, 21, 26, 32, and 38 y. Conclusion: -Compared Psychological Testing: IQ, Cognitive Function, and Mental Health -Hypothesis: Chronic use of cannabis leads to a *decrease in IQ* -Findings: *Significant Decline* in 2 groups of cannabis users: -->*Consistent* use that began at a *young age* -->*Diagnosis of dependence*

Cigarette vs. Marijuana Smoking Rate

Cigarette smoking rate *dipped below* marijuana smoking by 12th graders in 2015 for the first time ever

Efferent Signaling

Efferent: Sending messages *from the CNS* -->*actions to be taken* -Somatic Nervous System -->Skeletal Muscle-movement -Autonomic Nervous System -->*Smooth Muscle*: blood vessels, GI -->*Cardiac Muscle*: heart rate -->*Glands*: hormonal signals CNS-->PNS

NSAIDS (Step-1)

Examples: Aspirin, ibuprofen, naproxen, celecoxib Mechanism: Acts at the site of tissue injury to *inhibit production* of *prostaglandins* -->COX inhibitors -->COX enzymes metabolize prostaglandins, which are regulators of pain, fever, inflammation, etc.

Amplification

Hormone/drug-->Receptor-->Effectors-->Second Messengers-->Activation by second messengers

Endocannabinoid signaling

Induces *synaptic depression at excitatory synapses*

WHO Analgesic Ladder

Originally designed for *cancer pain* Step 1: NSAIDS Step 2: Opioid Step 3: Opioid+ Step 4: Opioid++

SFE Uses

SFE can be used as: 1. a sample preparation step for analytical purpose 2. on a larger scale, to either *strip unwanted material* from a product (e.g. decaffeination) or *collect a desired product* (e.g. essential oils)

Cellular Membrane

The cell membrane of the cell is a *phospholipid bilayer* containing many different molecular components, including proteins and *cholesterol*, some with carbohydrate groups attached