Neurotransmitter & Drugs 3 Flashcards
test 4 material
how are serotonin and melatonin synthesized?
tryptophan is coverted by tryptophan hydroxylase (rate-limiting step) into 5-HTP –> 5-HT –> N-acetyl-5-HT –> melatonin
what is the termination of action of serotonin?
reuptake by SERT and repackaging or reuptake and degradation by MAO into 5-HIA and 5-HIAA
where is melatonin released from?
the pineal gland
where are serotonin cell bodies located?
in the raphe nuclei
what are the types of serotonin receptors and what does serotonin regulate?
there are about 10 types of serotonin receptors, 1 is ionotropic (cation channel, 5-HT3) and the other 9 are metabotropic (Gi/o, Gs, or Gq), 5-HT1D is an autoreceptor, it is involved in regulation of sleep, mood disorders, OCD, and hallucinogenic action
what are some drugs that act on serotonin?
fluoxetine (prozac) is and SSRI that inhibits SERT which keeps serotonin in synapse and acts as a antidepressant, mescaline (6h), psilocybin (2-4h), and LSD (10-12h) are direct 5-HT agonists
what are the effects on MDMA and what causes them?
acts as an indirect monoamine agonist that increases serotonin (causes hallucinogenic effects) and inhibits reuptake of dopamine and norephinephrine and causes more vesicle release (causes stimulant effects and euphoria), also acts as an indirect oxytocin agonist that causes the release of oxytocin (causes social awareness and perception of closeness)
what are the negative effects of MDMA?
anxiety, paranoia, insomnia, hyperthermia, bruxism (compulsivity to put things in mouth), flu-like withdrawal, and tolerance
how is glutamate synthesized?
glutaminase converts glutamine (a non-essential amino acid) to glutamate (rate-limiting step), glutamate is then converted to GABA
what is the termination of action of glutamate?
reuptake by Glu neuron and repackaging, reuptake by astrocytes and back conversion to glutamine, or reuptake by postsynaptic neuron
what are the functions of glutamate?
can bind pre or postsynaptically, plasticity of learning and memory, excitotoxicity, Huntington’s and Alzheimer’s disease, seizures
what are some drugs that act on glutamine?
ketamine/PCP acts as an indirect NMDAR antagonist, and MSG acts as a direct glutamate agonist
what are the three subfamilies of ionotropic glutamate receptors?
NMDA, AMPA, and kainate
what are the characteristics of AMPAR and KAR?
allow Na+ in and K+ out, GluA1 AMPAR are also Ca2+ permeable and let Ca2+ in
what are the characteristics of NMDAR?
allow Na+, K+, and Ca2+ through the channel, requires glycine and glutamate to bind in order for channel to open, ligand and voltage-gated, slower kinetics
how do Mg2+, PCP, and Zn2+ play a role in NMDAR?
Mg2+ blocks channel so a depolarization must occur to repel the Mg2+, PCP can enter the channel and block the flow of ions, Zn2+ can also enter cell after the flow has started to block the channel and act as a negative feedback loop
what are the three subfamilies of metabotropic glutamate receptors?
group I, II, or III
what are the characteristics of metabotropic glutamate receptors?
can be excitatory or inhibitory depending on G-coupling, blocks Ca2+/Na+, group I is slow and excitatory and group II and III are slow and inhibitory, group II contains glutamate autoreceptors
