Psy106 Midterm 2
what regions of the brain control movement?
-brain and spinal cord: different motor systems that can simultaneously control particular types of movement -primary motor cortex (M1) is on the precentral gyrus in the frontal lobe, stimulation of primary motor cortex produces movement of the body, somatotopic organization, motor homunculus -supplementary motor area: frontal cortex -premotor cortext: involved in planning of movements which get executed via their connections with primary motor cortex, fMRI data show that when people execute or imagine executing a sequence of movements these areas are active
what happens when a photopigment is exposed to light?
-breaks the opsin and retinal connection -causes a change in membrane potential -changes the rate of glutamate release
what are projection systems?
-cell bodies in one place with long axons that extend to other regions/structures
what is the fovea?
-central region of the retina -mediates most acute vision -contains only cones
what is locus coeruleus?
-blue spot -is very active during wakefulness -involved NE in arousal -discharge rate increases when an animal is confronted with any novel or biologically relevant stimulus (fight or flight)
what are neurotransmitters?
-chemical released by a presynaptic element upon stimulation that activates postsynaptic receptors -NT are usually full agonists at the primary receptors site
what are noradrenergic drugs?
-propanolol and atenolol: "beta blockers" -propanolol: non-selective antagonist (beta1 and beta2) -atenolol: selective antagonist at beta 1 receptor -use of propanolol to treat PTSD, disrupt memory consolidation?
what are heteroreceptors?
-receptors located on the presynaptic button that are sensitive to a neurotransmitter that is DIFFERENT than the one released by the neuron -this is how NT systems interact
what are autoreceptors?
-receptors located on the presynaptic neuron that are sensitive ONLY to the neurotransmitter that it releases -almost always inhibitory -negative feedback
what is an extrafusal muscle fiber?
-responsible for muscle contraction -innervated by alpha motor neurons -single alpha neuron can innervate several muscle fibers -ratio varies on the precision of the muscle movement -muscles with precise movements such as fingers have a much lower ratio of alpha motor neurons to muscle fibers innervated
what are the glutamate receptors?
-there are both ionotropic and metabotropic receptors -ionotropic: AMPA: gates Na+, most common receptor causes EPSP Kainate: gates Na+ NMDA: specialized receptor that gates Ca2+ and Na+, Mg2+ requires glycine as cofactor, 6 binding sites, excitotoxicity -metabotropic: mGluR, 8 different types, many are presynaptic autoreceptors
What are monoamines?
-they all have one amine group -they have similar molecular structures so drugs tend to affect activity in all of them to some extent -catecholamines: all have a catechol ring (epinephrine EPI, norepinephrine NE, Dopamine DA) -indolamines (serotonin or 5 hydroxytryptamine 5-HT)
what are neuromodulators?
-they are neurotransmitters that act over long distances -they diffuse in extra cellular fluid -modulating effects rather than information-transmitting effects
why is a delicate balance of glutamate and GABA necessary?
-too much glutamate: epilepsy, excitotoxicity -too much GABA: no LTP
what are the different somatosenses sensitive to?
-touch: pressure and vibration -temperature: warm receptors and cold receptors -pain: 3 types of receptors high-threshold mechanoreceptors: respond to intense pressure (striking, stretching, pinching) 2nd type responds to extremes in heat, acids and capsaicin (chili peppers) 3rd type is sensitive to ATP: released during ischemia (migraine pain)
what are some causes of parkinsons disease?
-toxins: exposure to pesticides and herbicides increase the incidence of Parkinson's disease, MPTP -autosomal recessive juvenile parkinsonism: mutation in the parkin gene, toxic accumulation in protein in the cells that express this gene, SN cells express this gene
what is the lens?
-transparent onion-like layers that change shape to focus the incoming light on the retina -accomodation
what is the cornea?
-transparent outer layer at the front of the eye
how does reuptake work for GABA? how does breakdown occur?
-transporters -4 types -on axon terminals and astrocytes -catabolism via enzymatic breakdown: GABA aminotransferase GABA-T
how does 5-HT synthesis and catabolism occur?
-tryptophan: precursor for 5-HT, amino acid obtained from diet -tryptophan--> L-5-hydroxytryptophan (5-HTP) by enzyme trypophan hydroxylase -5-HTP is converted to serotonin (5-HT) by aromatic-L-amino acid decarboxylase (AADC) -reuptake transporters on presynaptic membrane -broken down by MAO-A and COMT (monoamine)
what are GABAergic Drugs?
-benzodiazephines (BZD): GABA allosteric agonist anxiolytic: reduces anxiety hypnotics: sleep inducing agents diazepham (valium) and alprazolam (xanax) -non-BZD hypnotics: GABA allosteric agonist Zolpidem (Ambien) Zalepon (Lunesta)
what are the receptors?
-there are 5 subtypes (D1-D5) -can produce EPSP or IPSP depending on which receptor subtype is activated
what are dopaminergic drugs?
-L-DOPA: indirect DA agonist, precursor loading: increases amount of DA produced, treatment for Parkinson's disease -Haloperidol (haldol): DA receptor antagonist, used as an antipsychotic/neuroleptic, treatment for schizophrenia, antagonist at the D2 receptors -cocaine and amphetamine: indirect DA agonist, DA reuptake blockers, increase DA 400-800% above normal physiological levels
what are the NE receptors?
-2 classes of receptors -alpha: 2 types, alpha1 (mixed) and alpha2 (inhibitory) -alpha1 involved with smooth muscle contraction -alpha2 is presynaptic/inhibitory, feedback loop to modulate NT release -beta: 3 types (excitatory) -beta1 involved in increasing heart rate -beta2 regulates smooth muscle contraction (bronchial) -beta3 contributes to lipolysis in fatty tissue
where is GABA found and released?
-40% of all brain synapses show GABA activity -found in projection systems: interaction/control of neuromodulators -interneurons release GABA, local inhibitory control over excitatory neurotransmission -inhibit the target neuron that postsyaptic GABA-A receptor immediately after it fires -prevents rapid firing -can also inhibit glutamate firing via GABA-B heteroreceptors
what are the reuptake transporters for glutamate?
-5 distinct types -1 is on axon terminals (presynaptic) -other 4 are on astrocytes -degredation: most glutamate is taken into astrocytes
what functions are serotonin involved in?
-5-HT involved in: -temperature regulation -sleep -learning and memory -sexual function -hormonal secretions -immune activity -stress -anxiety -aggression -depression
what are the 5-HT projection systems?
-9 clusters of cell bodies located in raphe nuclei of midbrain, pons, and medulla -2 will be discussed -dorsal raphe: contains serotonergic cell bodies that project to the cerebral cortex and basal ganglia -medial raphe has serotonergic cell bodies that project up to the cerebral cortex and hippocampus
what is acetylcholine?
-ACh is the primary neuromodulator secreted by efferent neurons of the CNS -terminology: acetylcholinergic or cholinergic synapses/neurons -1st to be discovered
what is the nigrostriatal DA projection system?
-Dopamine cell bodies in the substantia nigra project to and and have terminal buttons in the striatum (caudate and putamen) -involved in movement -SN: tegmentum in midbrain/mesencephalon
what are the GABA receptors?
-GABA-A: ionotropic receptor gates Cl-, activation causes IPSP -GABA-A has 5 binding sites: GABA site Benzodiazephine (BZD) site, alcohol probably binds here as well Barbiturate site Steroid site Picrotoxin site -GABA-B: metabotropic receptor that controls a K+ channel, activation causes IPSP
what is GABA and what does it do?
-Gamma-aminobutyric acid: inhibitory amino acid neurotransmitter -terminology: GABAergic synapses/neurons -primary inhibitory transmission in the brain -serves to keep excitatory Glu transmission in check
treatments for parkinson's disease?
-L-DOPA: eventually stops working because there are not enough SN DA neurons to increase DA output -DA agonists: side effects: dyskinesias and dytonias -pallidotomies: destruction of the GPi, often reduces rigidity and improves movement, PET studies show motor cortex activity pre-surgery is decreased; the activity increases to normal levels post-surgery -fetal tissue transplant: transplant fetal SNA cells to the patient's SN, good results in terms of recover of function, hard to get the tissue, 90% of the cells die before implantation
what are cholinergic drugs?
-Nicotine: agonist at nAChR, comes from tabacco plant -Black widow spider venom (latrotoxin): ACh agonist, triggers release of ACh, neuromuscular junction (where neurons connect to muscles: cholinergic; affected by latrotoxin) -botulinum toxin: ACh antagonist, prevents release of ACh by the terminals
what are the other catcholamines?
-Norepinephrine (NE): found in neurons in the ANS -Epinephrine (EPI): hormone produced by adrenals, also neurotransmitter in brain but limited -terminology: adrenergic and noradrenergic synapses/neurons -NE is more important as neurotrasmitter in the brain, almost every region of the brain receives input form noradrenergic neurons -NE is involved in arousal
what is the endplate potential?
-PSP that occurs in the motor endplate in response to ACh release -larger than an EPSP
what is the dorsolateral corticospinal tract?
-a descending motor pathway -control of independent limb movements -starts primary motor cortex -travels through pyramidal tract, decussates at medulla -travels in ventral horn of spinal cord (dorsolateral portion) -synapses on interneuron in ventral horn of spinal cord -synapses on motor neuron in ventral horn of spinal cord -synapses on muscle fiber in limb
what is a motor unit?
-alpha motor neuron, axon, and the associated extrafusal muscle fibers
what are the precursors for glutamate?
-alpha-ketoglutarate (from krebs cycle which creates ATP) -glutamine
what is intrafusal muscle fiber?
-also called muscle spindles -specialized sensory organs -arranged in parallel to extrafusal muscle fibers in order to detect muscle length -gamma motor neuron contracts the intrafusal muscle fiber -does not contribute much to force of muscle contraction -modifies the sensitivity to stretch of the fiber endings
what is the ventromedial corticospinal tract? what nuclei does it synapse on and for what?
-automatic movements, gross movements of the trunk, movements involved in posture and locomotion -sparts primary motor cortex -travels through pyramidal tract -synapses on brainstem nuclei, tectum in mesencephalon (visual/auditory location); vestibular nucleus (balance); reticular formation (regulation of typical movements; Motor nuclei for facial muscles) -synapses on interneuron in ventral horn of spinal cord -synapses on motor neuron in ventral horn of spinal cord -synapses on muscle fiber in limb
what is the primary visual pathway?
-axons from RGC converge and exit eye at optic disk, axons travel together as optic nerve -optic nerve travels back and undergoes partial decussation at the optic chiasm, 1/2 axons cross and 1/2 do not, axons from nasal 1/2 of retina cross & temporal axons do not -after optic chiasm it is called optic TRACT (because now CNS) -optic tract travels back and synapses in the lateral geniculate nucleus (LGN) of the thalamus -neurons in the LGN project to primary visual cortex in the occipital lobe (V1 or striate cortex)
how is acetylcholine synthesized? breakdown?
-choline+acetyl by ChAT -Choline: essential nutrient from diet and synthesized in body but in insufficient quantity -Acetyl: aceyl coenzyme A from glucose breakdown -ChAt: choline acetyltransferase Breakdown: acetylcholinesterase in synapse -Choline: Reuptaken into presynaptic terminal -Acetate: reuptake and excretion
Where is acetylcholine in the brain? What are the projection systems?
-cholinergic neurons are distributed widely throughout the brain -triggering REM sleep -Activating cortex to facilitate learning -formation of particular types of memories -usually ACh release in brain is excitatory -in periphery: released at cholinergic synapses at the neuromuscular junctions to produce muscle movements released in autonomic nervous system (ANS) in ganglia and at the target organs of the parasympathetic division
what is the vitreous humor?
-clear gelatinous substance inside
what are the differences between cones and rods?
-cones are in the fovea, have high acuity (sharpness of vision), little convergence, one cone is connected to one bipolar cell that is connected to one ganglion cell, 1:1:1 -rods are in the periphery, peripheral vision, lots of convergence, many rods converge onto a few bipolar cells which converge onto one ganglion cell, many: several: 1
what are the parts of the eye?
-cornea -iris -pupil -lens -viterous humor -retina -photoreceptors
what kinds of senses are in the somatosensory system?
-cutaneous senses -kinesthesia -organic senses
what is the mesolimbic dopamine projection system?
-dopamine cell bodies located in the ventral tegmental area (VTA) that project to and have terminal buttons in the nucleus accumbens (NAC) and amygdala -involved in reward and motivation -VTA: tegmentum in midbrain/mesencephalon
Epinephrine, norepinephrine synthesis and catabolism?
-dopamine is converted into norepinephrine by dopamine-beta-hydroxylase -norepinephrine is converted to epinephrine by the enzyme phrenylethanolamine N-methyltransferase PEA-MT -reuptake transporters: presynaptic membrane -breakdown: MAO-A, COMT -MAO-B was used by DA -COMT used by all catecholamines
what is the mesocortical projection system?
-dopaminergic cell bodies located in the VTA that project and have terminal buttons in the prefrontal cortex -involved in short-term memory, planning and problem solving
dopamine terminology, major projection systems, implications?
-dopaminergic synapses/neurons -movement -attention -learning -reward and motivation -projection systems: mesolimbic, mesocortical, nigrostriatal
how do muscles connect to bone? what is bending a joint called? straightening?
-muscles connected to bones at each end by tendons, tendons connect muscle fibers to bones -flexion: movement that tends to bend joints -extension: movement that tends to straighten joints -lifting up your food off the ground is a flexion movement, putting it down is extension
what are the somatosensory pathways?
-dorsal column/medial lemniscal pathway: localized information like fine touch and kinesthesia -dosal columns: axons from somatosensory receptors enter the CNS via spinal nerves and ascend in the ipsilateral spinal cord -axons cross (decussate) at the medulla and ascend (through the medial lemniscus) to the thalamus -synapse at the ventral posterior nucleus (VPN) of the thalamus -VPN projects to the primary somatosensory cortex (S1) in the parietal lobe
what is glutamate involved in?
-dynamic information processing -working memory -perception -voluntary muscle control -abnormal glutamatergic transmission is implicated in: -epilepsy -ischemic brain damage -anxiety -addiction
what is the result of the activation of a post-synaptic receptor?
-either IPSP or EPSP depending on type of receptor
what are serotonergic drugs?
-fluoxetine (prozac)-5-HT agonist: blocks the reuptake of 5-HT, selective serotonin reuptake inhibitor, treatment for depression, anxiety disorders and obsessive compulsive behavior -lysergic acid diethylamine (LSD)- 5HT2A receptor agonist, produces hallucinations
how is GABA synthesized?
-from glutamate by glutamate decarboxylase (GAD)
what are the two amino acid neurotransmitters?
-glutamate -GABA
what two NT accomplish most synaptic communication in the brain? what PSP do they usually cause?
-glutamate (excitatory) -GABA (inhibitory)
what are the synthesizing enzymes for glutamate?
-glutamate dehydrogenase -glutamine synthetase
what is the polysynaptic reflex arc?n
-golgi tendon organs detects muscle stretch -synpases on inhibitory interneurons that synapseon the alpha motor neuron of the same muscle -decreases the strenth of muscular contraction when there is a danger of damage to tendons or bones
what two other types of cells modulate activity?
-horizontal cells: transmit information in a parallel direction; combines information from adjacent photoreceptors -amacrine cells: transmit information in a parallel direction; combines information from adjacent and bipolar ganglion cells
basal ganglia in motor system? inputs? outputs?
-important part of motor system, destruction causes motor impairment -motor nuclei: cuadate, putamen, globus pallidus (internal and external divison) -inputs: primary motor cortex, primary somatosensory cortex, substantia nigra (SN): midbrain (remember the nigrostriatal dopaminergic pathway) -output: 3 cortical areas via the thalamus: thalamic nucleus: VA/VL, primary motor cortex, supplementary motor area, premotor cortex -motor nuclei in the brainstem: ventromedial pathway
what are glutamatergic drugs
-indirect antagonists at the NMDA receptor -phencyclidine PCP -ketamine: binding site in inside channel so it physically blocks the channel
what is serotonin?
-indolamine: serotonin -5-hydroxytryptaine -terminology: serotonergic synapses/neurons -5-HT seems to be involved in virtually every psychological function, yet total destruction of 5-HT does not result in death -some of the most useful drugs in psychiatry alter 5-HT activit, agonists at particular 5-HT receptors are potent hallucinogens
what does each AP cause for a muscle fiber?
-induces a contraction -depolarization of the muscle fiber opens V-D Ca2+ channels, Calcium enters the cytoplasm which triggers the muscle contraction -physical effects last longer than the AP because elasticity of muscle, time required to rid the cell of calcium -a rapid succession of APs can cause a muscle fiber to produce a sustained contraction
what do rods and cones have?
-inner and outer segments -lamellae: layers of membrane containing photopigments located in the outer segment -photopigments: special molecules embedded in the membrane that are responsible for transduction of visual information -photopigments have two parts: opsin (protein dye) bonded to a molecule of retinal
what is glutamate? how does it work? how many suspected amino acid transmitters are there?
-it is an excitatory amino acid (EAA) NT -8 suspected amino acid transmitters -terminology: glutamatergic synapses/neurons -point to point transmission
what is the optic disk?
-location of the exit point from the retina for the fibers of the ganglion cells that form the optic nerve -blind spot -do not normally perceive out blind spots
how does the basal ganglia loop project?
-loop between cortex and basal ganglia -frontal, parietal and temporal cortex project to the striatum -striatum projects to the globus pallidus (GP) -GP projects to VA/VL nuclei of the thalamus -VA/VL to motor cortex -basal gaglia is "informed" of planned movements and can influence these movements via this loop
what pathways are involved in schizophrenia?
-mesolimbic and mesocortical dopamine pathway dysfunction is involved
what is the retina?
-neural tissue that contains photoreceptors that is located on the inner surface of the posterior portion of the eye -layered and contains 3 main types of cells -photo receptors -bipolar cells: photoreceptors form synapses with them and they in turn synapse on the ganglion cells -retinal ganglion cells: axons=optic never that travels back to the brain activity
what is parkinson's disease?
-neurological disorder characterized by: muscular rigidity, slowness of movement, resting tremor, postural instability -caused by SN DA neurons dying, DA input to the striatum via SN facilitates movements -the lack of DA input results in an increase in the inhibitory output of the GPi (less inhibition of the inhibitor) so there is too much inhibition of motor cortex
what is the NMJ?
-neuromuscular junction: the terminal button of an efferent neuron and the membrane of the muscle fiber it synapses on
what are the ACh receptors?
-nicotinic (nAChR): ionotropic, primarily gates Na+, EPSP, Fast, 2 ACh molecules need to bind to activate the receptor -muscarinic (M): G-protein coupled receptors, 5 subtypes, different subtypes are coupled to different G-proteins, slower, most excitatory
what are the major NE projection systems/
-noradrenergic cell bodies located in the locus coeruleus in dorsal pons, that project and send terminals to widespread regions in the brain -most NE release is at axonal varicosities -axonal varicosities: beadlike swellings along axon branches that can release NT
what is the pupil?
-opening in the iris -regulates amount of light that enters the eye
how does the cerebellum play a role in the motor system? what are the different areas of the cerebellum?
-outputs to every major motor structure in the brain, cerebellar damage causes uncoordinated jerky movements -consists of 2 cerebellar hemispheres and 4 deep cerebellar nuclei -flocculonodular lobe: caudal end; involved in postural refelxes, damage: disturbances in posture and balance -vermis: intermediate zone; influences automatic behaviors and posture, damage: deficits in movements produced by the rubrospinal tract -lateral zone; control of independent skilled movements: calculates closely timed sequences of muscular contractions to execute rapid skilled movements, damage; weakness and decomposition of movement, impaired timing of ballistic movements -cerebellar cortex: control of arms and legs
what are kinesthesia sense?
-perception of body's own movements -stretch receptors in skeletal muscle: used to control movement
what is the iris?
-pigmented ring of muscles behind the cornea
Where are the receptors?
-post-synaptic receptors -pre-snynaptic receptors (includes autoreceptors) -heteroreceptors
how is dopamine synthesized?
-precursor for catecholamines is tyrosine, amino acid obtained from diet -tyrosine is converted to L-DOPA by the enzyme tyrosine hydroxylase (TH), TH is rate-liming step in DA synthesis -L-DOPA is converted to dopamine by the enzyme aromatic-L-amino acid decarboxylase (AADC), sometimes abbreviated DDC (dopa decarboxylase)
how does the M1 control movement?
-primary motor cortex controls movement via two descending motor pathway groups -lateral group: control of independent limb movements, particularly hand and finger movements, includes dorsolateral corticospinal tract, dorsolateral corticorubrospinal tract -ventromedial group: automatic movements, gross movements of the trunk, coordinated limb and trunk movements involved in posture, locomotion, includes ventromedial corticospinal tract, ventromedial cortico-brainstem-spinal tract
how is dopamine broken down?
-reuptake from synaptic cleft into presynaptic neurons: reuptake transporter protein in presynaptic membrane -monoamine oxidase (MAO): enzyme breaks down monoamines intraneuronally 2 forms: MAO-A and MAO-B MAO-B is found in dopaminergic terminal buttons Also in blood where it deactivates amines thereby preventing dangerous increases in blood pressure -catechol-O-methyltransferase (COMT): enzyme that breaks down catecholamines extraneuronally: synapse, glial cells, minor factor for catecholamine deactivation
what are the forms of opsin?
-rhodopsin: opsin found in rods -cone opsin: opsin found in cones -retinal: from vitamin A
what are the cutaneous receptors?
-ruffini's corpuscles: respond to sustained indentation of the skin (edges) -pacinian corpuscles: detect mechanical stimulation and rapid vibrations -meissner's corpuscles: detect light touch, low frequency vibrations -merkel's disks: respond to brief indentations of the skin (texture) -free nerve endings: detect pain, temperature, itch
what are organic senses?
-sense in the inner organs of the body -stretch and sometimes temperature
how do we get movement?
-sense the environment -select an appropriate response (decision) -plan the motor response -execute the motor response -requires interaction between sensory and motor systems
what are cutaneous senses?
-sensitivity to stimuli that involve the skin (touch) -pressure: mechanical deformation of the skin -vibration: fingers on rough surface (texture) -heating and cooling (temperature) -tissue damage
how does reflexive control of movement occur? what is the monosynaptic stretch reflex?
-spinal cord has some degree of autonomy -particular stimuli can elicit rapid response via neural connections in the spinal cord -monosynaptic stretch reflex: reflex in which a muscle contracts in response to being quickly stretched -control of posture -correction for weight added to a muscle
how is the eye held in place?
-suspended in orbits in the front of the skull -held in place and moved by 6 extraocular muscles attached to the sclera (white, fibrous covering)
what is the motor end plate?
-the postsynaptic membrane of a neuromuscular junction
what are photoreceptors?
-the receptor cells in the retina that transduce photic (light) energy into electrical potentials -rods: type of photoreceptor that is sensitive to low intensity light, vision in low conditions at night -cones: type of photoreceptor that is sensitive to different wavelengths of light, 3 kinds of cones: color vision, daytime and high acuity vision
what is an agonist? an antagonist? an allosteric site?
Agonist: a ligand that binds to produce a full effect ◦ Neurotransmitters are agonists ◦ A drug that facilitates the effects of a particular neurotransmitter on the postsynaptic cell Antagonist: a ligand that binds and produces no effect ◦ A drug that opposes or inhibits the effects of a particular neurotransmitter on the postsynaptic cell Allosteric site: other binding site on the receptor ◦ Remember what receptors look like?
what are the types of agonists?
Full agonist: ligand that binds & produces the full effect Partial agonist: ligand that binds & produces a partial effect (also referred to as having less intrinsic activity) Allosteric agonist (indirect agonist): ligand that binds to a different site on the receptor than the neurotransmitter & facilitates the actions of the neurotransmitter once it has bound
what are the types of antagonists?
Full antagonist: ligand that binds and produces no effect ◦ ligand that binds to the same site as the neurotransmitter & prevents it from binding Allosteric antagonist (indirect antagonist): ligand that binds to a different site on the receptor but prevents the neurotransmitter from having an effect once it binds
what are the four types of receptors?
Ionotropic receptor or ligand-gated ion channels ◦ An ion channel opens in response to ligand binding ◦ Can result in an EPSP or IPSP depending ion channel Metabotropic receptors or G-protein coupled receptors ◦ An intracellular cascade of events begins in response to agonist binding ◦ Can result in an EPSP or IPSP or a change in the intracellular environment depending on which type of G-protein the receptor is coupled to Enzyme-linked receptors (receptor tyrosine kinase) Cytoplasmic receptors: hormone binding
what are drug effects? what can they do?
Most of drug effects = receptor effects ◦ What the drug does at the receptor when it binds produces the effect Drugs can also: ◦ Affect production of neurotransmitters ◦ Synthesis is controlled by enzymes ◦ Drugs can affect the enzymes thereby affecting synthesis (increase or decrease) ◦ Affect storage & release of neurotransmitters ◦ Synaptic vesicles filled via transport molecules then neurotransmitter is released into synaptic cleft ◦ Affect transport molecules ◦ Inactivate axoplasmic transport of NT from cell body to terminal ◦ Interfere with vesicle packaging & release ◦ Impair or enhance reuptake & destruction of neurotransmitters ◦ Neurotransmitter is either taken back up into the presynaptic neuron & broken down intraneuronally (or if no reuptake then in the cleft)
what is psychopharmacology? drug effects? drug sites of action? what are examples of such? what are drug mechanisms of actions? what is a ligand? endogenous and exogenous?
Psychopharmacology: study of the effects of drugs on the NS & behavior Drug effects: the changes we can observe in an organism's physiological processes and behavior Drug sites of action: location at which the drug molecules interact with molecules on or in the cell thereby affecting the processes in these cells ◦ Receptors; enzymes; transporter proteins; etc. Drug mechanism of action: how the drug produces its effects Ligand: a chemical that binds to a receptor ◦ Endogenous: made in the body ◦ Neurotransmitters & neuromodulators ◦ Exogenous: not made in the body ◦ Drugs & biological toxins