The Influence of Drugs on Neurotransmitters
Endorphins
"morphine within"--natural, opiate-like neurotransmitters linked to pain control and to pleasure.
100 tillion
# of synapses in the brain
Dr. William Silkworth
80 years ago, __________________ suggested that alcoholism (addiction) came from a combination of an obsession of the mind coupled with an allergy/illness of the body. These observations have been validated by modern neuroscience. Over the years, drug abuse and dependence have been examined from multiple perspectives.
Amphetamine
A central nervous system stimulant that is used in the treatment of attention deficit hyperactivity disorder, narcolepsy, and obesity.
Neurotransmitters
A chemical substance that is released at the end of a nerve fiber by the arrival of a nerve synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.
ASAM criteria
A collection of objective guideline that gives clinicians a way to standardize treatment planning and where patients are placed in treatment, as well as how to provide continuing, integrated care and ongoing service planning.
Blood brain barrier
A drug will reach the gateway to the central nervous system.
Half life
A drug's ___________ is a measure of time it takes for half the dose to be inactivated or eliminated.
Synapse
A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
Dopamine
A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.
Reuptake
A process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane.
Categories to judge a person's level of use
Abstinence Experimentation Social/recreational sue Habituation Abuse Addiction
Reflex
An immediate reaction triggered by the old brain.
Reabsorbed
As neurotransmitters complete their job, they are released back into the synaptic gap and are _________ by the sending nerve cell reuptake ports and returned to the vesicles, ready to fire again.
Heroin
Block release of neurotransmitters from vesicles.
Dendrites
Branchlike parts of a neuron that are specialized to receive information.
Axon
Carries the message from the cell body to the terminals.
Antagonists
Chemical substances that block or reduce a cell's response to the action of other chemicals or neurotransmitters.
Reuptake Inhibitor
Chemical that binds to the terminal buttons and prevents reuptake, thereby causing an excess of that NT
Diathesis-stress theory of addiction
Combination Predisposition to addiction as a result of genetic and environmental influences, which, when further stressed by the use of substances or engaging in certain behaviors, alters neurochemistry, brain function, and even epigenetics to the point that return to normal behavior is extremely difficult.
Central Nervous System
Comprises the brain and spinal cord.
Old brain
Consists of brainstem, cerebellum, and mesocortex (mid brain), which contain the limbic system.
Autonomic system
Controls involuntary internal functions such as circulation, respiration, digestion, etc.
Psychoactive drugs
Directly affect the neurochemistry and anatomy of the CNS, causing mental, emotional, and physical changes.
Addictive disease model
Disease of addiction is a chronic, progressive, recurring, incurable, and potentially fatal condition that is generally a consequence of genetic irregularities in brain chemistry and anatomy that may be activated by the particular drugs.
Agonists
Drugs that bind to receptors and mimic or facilitate the effects of neurotransmitters are called ________.
Partial agonists
Drugs that bind to receptors and partly mimic the effects of neurotransmitters are called ____________
Inverse agonists
Drugs that bind to receptors and stabilize the receptor in its inactive state by hyperpolarizing it so that it cannot react are called_________
Antagonists
Drugs that bind to receptors but don't activate them, thereby blocking neurotransmitters are called _________
Agonists
Drugs that increase the action of a neurotransmitter
Fasciculus retroflexus
Due to damage of the _________________, which can occur very early in chronic drug use; young people who drink heavily can damage this nerve pathway after just a few binges.
Behavioral/environmental model
Emphasizes environmental and developmental influences. Environmental factors can change brain chemistry.
Central Nervous System
Enables us to remember, reason, create, think, to respond.
Endogenous opioids
Endorphins and enkephalins are called __________, this means they are produced by the body.
Substance use disorder
Essential feature of a _____________ is a cluster of cognitive, behavioral, and physiological symptoms indicating that the individual continues using the substance despite significant substance related problems.
Morphine
Example of an agonist.
Atropine
Example of antagonist
Cocaine
Example of reuptake inhibitor.
Message transmission
Excitatory neurotransmitters increase cell firings by opening the gate and allowing positive ions into the neuron. Inhibitory neurotransmitters reduce cell firings by allowing negative ions into the neuron, pushing positive ions out. When enough excitatory neurotransmitters cause sufficient movement of the positively charged ions and reaches a certain action potential, it fires the signal. If enough inhibitory neurotransmitters keep the voltage below the action potential, the cell is inhibited from firing.
Cocaine
Force release of neurotransmitters by entering the presynaptic neurons, causing more to be released than naturally.
Nicotine
Has been shown as a precursor for cocaine and methamphetamine use.
Action potential
If enough synapses collectively create enough ______________ in the next nerve cell, the electrical charge can travel to the next synapse where it is again converted into a chemical signal for the next synapse.
Up regulation
If there are too few neurotransmitters available to trigger the message, the receiving neuron will increase the number of receptor sites to provide the few remaining neurotransmitters with more receptors to active.
Down regulation
If there are too many neurotransmitters, it retracts many of the receptor sites, slowing down the message transmission. Excessive use can cause a permanent decrease in receptor sites.
Go switch/stop switch
In a person with addiction, the ________ switch is overactive and the ___________ switch is either underactive or unable to communicate the shut it down message back to the survival/reinforcement circuit, so the brain is stuck in a do it again more.
Monoamines
Includes dopamine, which is the most crucial neurotransmitter involved in both substance and process addictions, the reward chemical. Includes serotonin, which helps control mood stability.
Common ways drugs enter the body
Inhalation Injection Mucous membrane absorption Oral ingestion Contact absorption.
Heart meds
Inhibit enzyme that helps synthesize neurotransmittesr to slow the nerve cell's production of neurotransmitters.
Treatments for craving
Lack of dopamine, augentation, buprenorphine and methadone increase dopamine, stabilizes craving, effective behavioral therapy.
Stop switch
Located mostly in the new brain. When the need has been satisfied, the stop switch shuts down the go switch and the do ti again message ceases. This signals the cells to stop releasing dopamine, which shuts down these messages.
Four groupings of major neurotransmitters
Monoamines Amino acids Opioid peptides Miscellaneous.
Exogenous opioids
Morphine, heroin, and other opium derivatives or synthetics are called _______________, this means they are produced externally from the body.
Survival/reinforcement circuit Go Switch
Normally, the go switch does three things when activated: Tells us what we are doing is necessary for survival, giving us a feeling of satisfaction. Tells us to remember what we did to survive. Then tells us, "Do more of whatever you did-do it again and again until satisfied-it is necessary for your survival.
Cell body
Nourishes the cell and keeps it alive.
Action potential
Occurs when a neuron sends information down an axon, away from the cell body. Neuroscientists use others words, such as a spike or an impulse. An explosion of electrical activity that is created by a depolarizing current.
Message transmission
Occurs when the incoming electrical signal forces the release of neurotransmitters from the vesicles. This sends them across the synaptic gap. On the other side of the gap, the neuro transmitters slot into precise and complex receptor sites. These receptor sites, when activated by the neurotransmitter, cause an ion gate to open, allowing an electrical charge to enter or exit.
Memories
One of the things that lasts the longest is the ________________ associated with drug use and drug abuse.
Antidepressants
Prevent neurotransmitters from being reabsorbed into the sending neuron, causing them to remain in the synapse to slot into receptors agin, inducing more intense effects.
New brain (neocortex)
Processes information coming from the old brain, from different areas of the new brain, and from senses via the PNS. Allows us to speak, reason, create, remember, make decisions, and then act, while the old brain simply reacts. Craving can override the new brain's rational arguments. The old brain acts four or five times more rapidly than the new brain.
Central Nervous System
Psychoactive drugs can alter the information sent to the brain from the environment.
Dendrites
Receive signals from other nerve cells and relay them through the cell body.
Central Nervous System
Receives messages from the PNS, analyzes them, and then sends responses.
Bloodstream
Regardless of how a drug enters the system, it is eventually distributed by the ___________ to the rest of the body.
Old brain
Regulating physiological functions of the body (respiration, heartbeat, temperature, hormone, release, muscles). Experiencing basic emotions and cravings (anger, fear, hunger, thirst, lust, pain, pleasure). Imprinting survival memories (that tastes good, this odor is bad). When an individual uses a psychoactive drug, most often it is the old brain that remembers the experience and how it felt. Craving to use almost always resides in the old brain.
Opioids peptides
Related to pain
Terminals
Relay messages to the dendrites, cell body, or terminals of the next nerve cell.
Tissue dependence
Results from biological adaptation of the body due to prolonged use of a drug. The tissues and organs become dependent on the drug simply to stay functional.
Liver
The ________ is the key metabolic organ, it breaks down or alters the chemical structure of drugs.
Kidneys
The ___________ are the primary excretory organs.
Hijacking
When a psychoactive drug actives this pathway, the result is a feeling of satisfaction, a high, or pain relief, which prompts the go switch to urge the person to do it again, do it again. For substance abusers who have altered brain chemistry, the go switch is more powerful than normal and the stop switch becomes dysfunctional and does not shut off the craving, so the person continues to use because there are no instructions to stop.
25%-30%
_____ of people who get exposed to heroine will become addicted. This has the highest addiction rate.
15 million
_______ alcohol related addictions.
3 million
_______ opioid related addictions.
50%
_________ of the risk for addiction is genetic.
21 million
_________ people in the US have the disease of addiction.
Autoreceptors
The amount of neurotransmitters available for message transmission is constantly monitored by _____________ on the sending neuron.
Survival/reinforcement circuit Go Switch
The area of the brain that encourages a human to perform or repeat an action that promotes survival. Its normal function is to reinforce an action that promotes survival. This part of the brain is most affected by psychoactive drugs. This survival/reinforcement circuit, located in the old brain, acts as a go or more switch.
Academic model
The body adapts to the substance sin order to achieve homeostasis, which reinforces addiction.
Metabolosim
The body's mechanism for processing, using, and inactivating a substance.
Pharmacokinetics
The key factors in _____________: Route of administration Speed of transit to the brain Rate of metabolism Process of elimination Affinity for nerve cells and neurotransmitters.
Rapidly
The more ___________ a psychoactive drug reaches its target in the CNS, the greater its reinforcing (Addictive) effect.
Vesicles
The neurotransmitters are stored in tiny sacs called ___________ that travel through the neuron to the axon terminals.
Pharmacokinetics
The process by which a drug is absorbed, distributed, metabolized, eliminated, and excreted
Excretion
The process of eliminating the substance and its metabolites from the body.
Synaptic cleft
The space between neurons at a nerve synapse across which a nerve impulse is transmitted by a neurotransmitter. Also called a synaptic gap.
Hijacking
The stop switch is often totally disabled by chronic drug use, rendering it useless to stop even a mild craving from turning into drug use. The overriding message at a subconscious level is if you don't do it again, you will die.
Hijacking
The survival/reinforcement and control circuits have been _________, so the individual continues to use drugs, tricked into sensing that survival depends on it. As chronic heavy use continues and the neurochemistry changes, the do it again message becomes impossible to ignore, resulting in drug seeking/using behavior regardless of the amount of pleasure the use experiences or the destruction the user ultimately causes.
Axon terminal
The very end of a branch of a nerve's axon, a long slender nerve fiber that conducts electrical signals to a nerve synapse (the gap between nerve cells). The signal then moves across the synapse to another axon by means of a neurotransmitter.
Somatic system
Transmits sensory information about the environment and limb and muscle position; transmits instructions from the CNS back to the muscles, allowing the body to respond appropriately.
