CH. 8 GABA Flashcards
what does GABA stand for
gama-aminobutyric acid
what is GABA’s function
primary inhibitory transmitter in the brain
what is another example of and inhibitory transmitter? where was it found?
glycine
back of the brain
what neurons use GABA?
medium spiny neurons in striatum
basal ganglia in general
projection neurons intermixed within monoamine cell groups
interneurons
what is the main role of GABA transmission
filter information and regulate firing patterns
disinhibition
what can happen to the body with reduced GABA activity?
seizures
what is an example of a disinhibition connection in the brain
pallidum is always firing GABAergic signals to motor region
ventral striatum activation sends GABA signal to pallidum, allowing for activation of motor region
what is the precursor to GABA
glutamate
what is the enzyme that synthesizes glutamate to GABA
glutamate decarboxylase (GAD)
what is the enzyme that moves GABA into vesicles?
vesicular GABA transporter (VGAT)
true or false; some vesicles contain varying amounts of GABA and another NT
true
what is GAT1 through 3
GABA’s reuptake transporter
what GABA reuptake transporter is found on the presynaptic terminal?
GAT-1
what GABA reuptake transporter is found on the astrocytes?
all three (GAT1-3)
what is the glial reuptake process of GABA
metabolized to glutamate and succinate
metabolized back to glutamine
released by astrocyte back to the presynapse
what enzyme metabolizes GABA to glutamate?
GABA aminotranferase (GABA-T)
what are the two main type of GABA receptors?
GABA-A
GABA-B
what kind of receptor is GABA-A
ionotropic
what does the GABA-A receptor do?
opens when activated
allows inflow of Cl-
hyperpolarizes the cell
how many subunits do GABA-A receptors have?
5, different combinations of 4 different types
what kinds of sites do GABA-A receptors have
GABA binding site
inside channel pore
allosteric binding site
neurosteroids binding site
agonist that binds to the GABA binding site
muscimol
what is muscimol
psychedelic mushrooms
Competitive antagonist that binds to the GABA binding site
bicuculline
non-competitive antagonist that binds to inside of channel pore
picrotoxin
what does picrotoxin do? what is the effect?
physically blocks the ion pore channel
induces seizures
positive allosteric modulator that sticks to the allosteric binding site of the GABA-A receptor
benzodiazepine (BDZ)
barbituates
BDZ drug example
diazepam
store name for diazepam
valium
barbituate example
phenobarbitol
BDZ effects
reduces anxiety
sleep/sedation
reduces REM sleep
what molecule acts as a similar way to BDZ but binds in a different spot on the GABA-A receptor?
neurosteroids
what other molecule can bind at the BDZ site? what is it’s effect?
inverse agonist
impedes effects of GABA on the channel
what kind of receptor is the GABA-B receptor?
metabotropic
how many subunits does the GABA-B receptor have?
2
how does the GABA-B receptor work on the postsynapse
opens K+ channel and inhibiting cAMP formation
what is the function of GABA-B receptors on the presynapse?
autoreceptors and heteroreceptors
GABA-B receptor agonist
baclofen
baclofen function
muscle relaxant
experimental alcoholism treatment
GABA-B receptor antagonist
saclofen
saclofen function
convulsant used in research
