Psychopharmacology and Neurotransmitters Flashcards
What is a drug?
Exogenous substance (not manufactured by the body), significantly alters neural activity, not needed for normal function, effective at low doses
What are agonists and antagonists?
Agonists FACILITATE postsynaptic effects – increasing effects
Antagonists INHIBIT postsynaptic effects – decreasing effects
What is a direct agonist and direct antagonist?
direct agonist: mimics neurotransmitter – drug stimulates postsynaptic receptors
direct antagonist: postsynaptic receptor blocker
What is noncompetitive binding?
Noncompetitive binding: neurotransmitter binds to an alternative site on the same receptor/enzyme but leaves space for another neurotransmitter to also bind to the same space, but this will inhibit other transmitters from binding there
Indirect agonist: binds to alternative site, AIDS ion channel opening
Indirect antagonist: binds to alternative site, STOPS ion channel opening
What is a receptor blocker? What is an auto receptor?
Autoreceptor: located in the presynaptic membrane that either stimulates or inhibits the production of specific neurotransmitters (agonist)
Receptor blocker: ligand or drug that blocks or dampens a biological response by binding to and blocking an autoreceptor rather than than activating it (antagonist)
What are the direct neurotransmitters in the CNS?
Glutamate – depolarization (EPSP)
GABA – hyperpolarization (IPSP)
Glycine – lower brain stem and spinal cord (IPSP)
What are neuromodulators?
Neuromodulators activate or inhibit functional neural circuits (most neurotransmitters have modulating, not direct effects)
What are the amino acids in the CNS?
Glutamate – excitatory neurotransmitter
Glutamate has an NMDA receptor (plays role in memory) and contains NMDA antagonists like alcohol and PCP
GABA – inhibitory neurotransmitter
Benzodiazepines are indirect GABA-A agonists with anxiolytic effects and alcohol is also a GABA agonist
Glycine – inhibitory in lower CNS (brain and spinal cord)
What is Acetylcholine and what are its functions?
Acetylcholine is a neurotransmitter (neuromodulator) that plays a role in memory, learning, and REM sleep in the CNS
It is made from choline and acetyl-CoA and is deactivated by acetylcholinesterase
This neurotransmitter attaches to nicotinic receptors (skeletal muscles and CNS) and muscarinic (ANS and CNS)
Agonist (increases effects): black widow spider venom
Antagonist (decreases effects): botulinum toxin
What are the monoamines and what are their classifications?
Catecholamines: dopamine, norepinephrine, epinephrine, deprenyl, resperine
Indolamine: Serotonin
What are the Catecholamines?
Dopamine: can be excitatory or inhibitory, depending on receptor – involved in movement, attention, learning, reinforcement
– made from L-trytophan
Norepinephrine: in ANS and CNS – involved in alertness and wakefulness
Epinephrine: secreted by adrenal medulla as a hormone and adrenergic neurons – plays sympathetic role in ANS
Deprenyl: MAO inhibitor and agonist for dopamine and norepinephrine
Reserpine: antagonist for dopamine and norepinephrine
What are the Indolamine?
Serotonin (5-HT): involved in eating, pain sensitivity, dreaming, arousal, and mood
effects depend on receptor type and serotonin can bind to lots of receptors
agonist: fluoxetine – blocks reuptake
antagonist: PCPA – blocks synthesis of 5-HT; used in research
What are the neural peptides and lipids?
Neuropeptides: amino acid chains
– endogenous opioids: endorphins and enkephalins
– naloxone: opioid receptor blocker (antagonist)
Lipids: insoluble in water
– endocannabinoids: natural ligands for THC receptors
What are the classes of Opioids?
endogenous opioids: come from body – endorphins and enkephalins
opium alkaloids (opiates): derived from opium poppy – opium, morphine, codeine
semi-synthetic opioids: synthesized from opium – heroin, oxycodone
synthetic opioids: created in a lab – fentanyl, methadone
