Neuro B6 Flashcards
(28 cards)
Almost all transmitters bind to more than one type of receptor. So when these transmitters bind do they exert an excitatory inhibitory effect?
depends on the type of receptor, either can happen.
Is it the nature of the receptor or the transmitter that dictates cellular effects?
the receptor!
Cholinergic neurons of the rostral pons project where?
to the brainstem, thalamus, hypothalamus, cerebellum, basal ganglia and other cholinergic cells of the basal forebrain
where do cholinergic neurons of the basal forebrain project to?
cortex, hippocampus and amygdala
postganglionic autonomic cells receive input from what preganglionic neurons?
cholinergic, releasing acetylcholine
why is an ionotropic receptor for ACh called the nicotinic receptor?
high affinity for nicotine (hence why if you smoke you hit the nicotinic receptors)
explain the process of glutamate recycling? (reminder glutamate is an Amino Acid transmitter)
- terminal and astrocytic glutamate trasnsporters take up extracellular glutamate
- Glutamine synthase metabolizes glutamate to form glutamine in astrocytes
- Glutamine exits astrocytes and enters neurons through glutamine transporters.
- Intraneuronal glutaminase converts glutamine to glutamate for reloading into vesicle
can aspartate use the glutamate uptake transporter?
yes known as the glutmate-aspaartate transporter
describe the AMPA/Quisqualate ionotropic glutamate receptor
Agonist and provokes the influx of Na and efflux of K
describe the Kainate ionotropic glutamate receptor
Agonist that provokes the influx of Na and efflux of K
describe the NMDA ionotropic glutamate receptor
- Agonists will open the central pore for the influx of Ca and Na provided that glycine occupies a strychnine insensitive binding site
- This will cause enough depolarization so that Mg will exit
(hence this receptor is all about calcium dependent process)
There are eight known mGluRs (metabotropic glutamate receptors), what are the three groups?
Grp 1: mGLURs typically excite
Grp 2: mGLURs typically inhibit
Grp 3: mGLURs typically inhibit
GABAa receptors have allosteric binding sites for what two classes of drugs?
benzodiazepines and barbiturates
GABAa receptors are permeable to Cl- normally and can control the equilibrium potential for Cl-. What happens to Cl levels when benzodiazepines or barbiturates bind?
with the binding of either barbiturates or benzodiazepines, GABA tends to trigger larger Cl currents.
GABAb receptors are metabotropic, with G-protein mediated coupling to calcium and potassium channels. What do agonists at axoaxonic synapses featuring GABAb receptors do to ion movement?
reduce Ca influx and therefore this limits the exocytoic release of transmitter.
GABA has two receptors on the post synaptic neuron, what are they/
GABAa and GABAb
How does the GABAb receptor work?
through second messenger system, Ca channel suppress and K channels enhance. (so basically this system increases K efflux by decreasing Ca influx)
How does ionotropic glycine receptors work?
act as ligand gated Cl channels. (note that can be blocked by strychnine this would be an antagonist)
where do we see glycinergic neurons?
exert local inhibitory actions in the retina and the gray matter of the brainstem and spinal cord
Once dopamine is released into the synaptic cleft, what happens to it?
- some is reloaded into vesicles
- some is metabolized by MOA in the liver
- Or it can be actively transported to the post synaptic cell for metabolism by COMT
The substantial nigra projection pathway?
to the caudate and putamen to regulate motor function (think parkinsons dz).
The ventral segmental area pathway?
prefrontal cortex nucleus accumbens (fun center or brain) limbic structures (think schizophrenic ppl)
The hypothalamic arcuate nucleus?
dumping of DA into the hypophyseal portal system for suppressing the release of prolactin
there are five known metabotropic dopamine receptors that form two main groups, what are they?
D1 (d1 and d5) —-> increase in production of cAMP
D2 (d2,d3,d4) —-> decrease production of cAMP
