PSYC304 Exam 3

reuptake transporter

• transport certain release nts back to presynaptic terminal

• neurotransmitter specific

• important drug target (cocaine, SSRIs)

autoreceptor

• expressed on presynaptic side

• receptor for a neurotransmitter that is expressed on the same neuron that releases that nt

• decrease further release of that neurotransmitter

• provides negative feedback

• good drug target

retrograde signaling

• on demand synthesis

• decrease presynaptic neurotransmitter release (inhibiting calcium ion influx)

two categories of neurotransmitters

• small molecule transmitters

• peptide transmitters (neuropeptides)

small molecule transmitter (classical)

• acetylcholine

• amino acids

• monoamines

• purines

neuropeptide transmitters

• short complex molecule proteins

• contains 3-36 amino acid residues

difference between neurotransmitter and hormones

neurotransmitters act fast across tiny nerve gaps, while hormones act slowly by traveling through the bloodstream

direct agonist

indirect agonist

direct antagonist

indirect antagonist

dose-response curve

intravenous administration

• peripheral route of drug administration

• directly injected into bloodstream

intracerebral administration

• directly into the brain

• usually for animal study

• used when blood brain barrier cannot be passed

intrathecal administration

• reach CSF through subarachnoid space surrounding spinal cord or brain

intracerebroventricular administration

• administered into the ventricle

  • ex. chemotherapy reservoir

ED50

dose required to produce 50% of the max effect (potency of drug)

LD50

dose that leads to the death of 50% of subjects

theraputic index

(margin of safety) difference between ED and LD; defines the range over which a drug can be used safely

affinity

how well a ligand bonds to a receptor

potency

the amount of drug needed to produce a biological response of a certain magnitude

tolerance

a “decrease“ in the effectiveness of a drug that is administered repeatedly

opioid overdose (price of tolerance)

naloxone

sensitization

an “increase“ in the effectiveness of a drug that is administered repeatedly

acetylcholine in the PNS

• neuromuscular junction

• autonomic nervous system

acetylcholine in the CNS

• produced in basal forebrain and brain stem

• attention, wakefulness, learning, and memory

where acetylcholine is produced in the CNS

basal forebrain and brainstem

two main acetylcholine postsynaptic receptors

• nicotinic and muscarinic

drugs that act on on ACh system

• botox

• black widow spider venom

• dietary choline

• nicotine

• muscarine

• curare

• atropine

role of adenosine

• neuromodulator (neuronal inhibition, used for sleep)

how does caffeine work?

• acts as antagonist for adenosine receptors (metabotropic and blocks A1 and A2A receptors)

primary effect of glutamatergic transmission

mainly excitatory and depolarization

two main postsynaptic ionotropic glutamate receptors

• AMPA and NMDA

AMPA glutamate receptors

• fast EPSPs at brain and spinal cord

• permeable to Na+ but not calcium

• glutamate binds in order to open

NMDA glutamate receptors

• limited role in normal synaptic transmission

• passes both calcium and sodium and K+

• glutamate and glycine (co-agonist) must bind; Mg2+ block must be removed

• at least six binding sites

how PCP works

• indirect NMDA receptor antagonist

• responsible for psychomimetic effects of PCP and related drugs of abuse

  • structurally similar to Ketamine

how Ketamine works

• indirect antagonist for NMDA

• rapid acting antidepressant

• usually used as a dissociative anesthetic for animals

primary effect of of GABAergic transmission

hyperpolarization due to influx of Cl- that comes in after the GABA-A receptor is binds with GABA

main postsynaptic GABA receptors

GABA-A and GABA-B

difference between GABA-A antagonist and agonist

• a GABA-A agonist activates the GABA-A receptor to calm brain activity

• GABA-A antagonist blocks the receptor and increases brain excitement

benzodiazepine

• anti-anxiety agents + muscle relaxants

• increases frequency of channel opening in response to GABA

• GABA agonist

barbituates

• anesthesia + control of epilepsy

• prolonged duration of GABA channel opening

• GABA agonist

picortoxin

• pro-convulsant

• decreases channel open time

• GABA antagonist

location of dopaminergic neurons

ventral tegmental area

dopaminergic pathways

• mesocortical, mesolimbic, mesostraital

types of dopamine receptors

D1 and D2

drugs that act on dopamine transmission

classical antipsychotic drugs

location of serotonergic neurons in the brain

raphe nuclei

function of the serotonergic pathway in the brain

monoamine hypothesis of depression

depression is due to deficiency of monoamine neurotransmitters such as norepinephrine and serotonin

limitation of monoamine hypothesis of depression

1. most TCAs and SSRIs take 3-4 weeks of use to reduce symptoms

2. some individuals don’t experience improvement

3. diets that exclude tryptophan do not produce depression

4. enhancing cholinergic transmission has been shown to improve depression and anxiety disorders

three major endogenous opioids

opioid receptor that is primary target for endorphins

active ingredient in marijuana responsible for “high“

“retrograde signaling“ mediated by endocannabinoids

examples of effects of marijuana

what is emotion

what conveys emotion

facial feedback hypothesis

where is emotion localized in the cortex

which hemisphere is lateralized for emotional processing?

limbic system

brain area for disgust

brain area for fear response

amygdala

brain area for defensive agression

brain area for predatory agression

reactive agression

appetitive agression

major contributor to sex difference in aggression

testosterone

period where females exhibit elevated aggressive behaviors

brain area responsible for love

mesostraital

mesolimbic

mesocortical