Neuro B6

Question 1

Almost all transmitters bind to more than one type of receptor. So when these transmitters bind do they exert an excitatory inhibitory effect?

Answer 1

depends on the type of receptor, either can happen.

Question 2

Is it the nature of the receptor or the transmitter that dictates cellular effects?

Answer 2

the receptor!

Question 3

Cholinergic neurons of the rostral pons project where?

Answer 3

to the brainstem, thalamus, hypothalamus, cerebellum, basal ganglia and other cholinergic cells of the basal forebrain

Question 4

where do cholinergic neurons of the basal forebrain project to?

Answer 4

cortex, hippocampus and amygdala

Question 5

postganglionic autonomic cells receive input from what preganglionic neurons?

Answer 5

cholinergic, releasing acetylcholine

Question 6

why is an ionotropic receptor for ACh called the nicotinic receptor?

Answer 6

high affinity for nicotine (hence why if you smoke you hit the nicotinic receptors)

Question 7

explain the process of glutamate recycling? (reminder glutamate is an Amino Acid transmitter)

Answer 7

1. terminal and astrocytic glutamate trasnsporters take up extracellular glutamate
2. Glutamine synthase metabolizes glutamate to form glutamine in astrocytes
3. Glutamine exits astrocytes and enters neurons through glutamine transporters.
4. Intraneuronal glutaminase converts glutamine to glutamate for reloading into vesicle

Question 8

can aspartate use the glutamate uptake transporter?

Answer 8

yes known as the glutmate-aspaartate transporter

Question 9

describe the AMPA/Quisqualate ionotropic glutamate receptor

Answer 9

Agonist and provokes the influx of Na and efflux of K

Question 10

describe the Kainate ionotropic glutamate receptor

Answer 10

Agonist that provokes the influx of Na and efflux of K

Question 11

describe the NMDA ionotropic glutamate receptor

Answer 11

1. Agonists will open the central pore for the influx of Ca and Na provided that glycine occupies a strychnine insensitive binding site
2. This will cause enough depolarization so that Mg will exit
   (hence this receptor is all about calcium dependent process)

Question 12

There are eight known mGluRs (metabotropic glutamate receptors), what are the three groups?

Answer 12

Grp 1: mGLURs typically excite
Grp 2: mGLURs typically inhibit
Grp 3: mGLURs typically inhibit

Question 13

GABAa receptors have allosteric binding sites for what two classes of drugs?

Answer 13

benzodiazepines and barbiturates

Question 14

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?

Answer 14

with the binding of either barbiturates or benzodiazepines, GABA tends to trigger larger Cl currents.

Question 15

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?

Answer 15

reduce Ca influx and therefore this limits the exocytoic release of transmitter.

Question 16

GABA has two receptors on the post synaptic neuron, what are they/

Answer 16

GABAa and GABAb

Question 17

How does the GABAb receptor work?

Answer 17

through second messenger system, Ca channel suppress and K channels enhance. (so basically this system increases K efflux by decreasing Ca influx)

Question 18

How does ionotropic glycine receptors work?

Answer 18

act as ligand gated Cl channels. (note that can be blocked by strychnine this would be an antagonist)

Question 19

where do we see glycinergic neurons?

Answer 19

exert local inhibitory actions in the retina and the gray matter of the brainstem and spinal cord

Question 20

Once dopamine is released into the synaptic cleft, what happens to it?

Answer 20

1. some is reloaded into vesicles
2. some is metabolized by MOA in the liver
3. Or it can be actively transported to the post synaptic cell for metabolism by COMT

Question 21

The substantial nigra projection pathway?

Answer 21

to the caudate and putamen to regulate motor function (think parkinsons dz).

Question 22

The ventral segmental area pathway?

Answer 22

prefrontal cortex 
nucleus accumbens (fun center or brain) 
limbic structures (think schizophrenic ppl)

Question 23

The hypothalamic arcuate nucleus?

Answer 23

dumping of DA into the hypophyseal portal system for suppressing the release of prolactin

Question 24

there are five known metabotropic dopamine receptors that form two main groups, what are they?

Answer 24

D1 (d1 and d5) —-> increase in production of cAMP

D2 (d2,d3,d4) —-> decrease production of cAMP

Question 25

what converts dopamine to norepinephrine?

Answer 25

dopamine-beta-hydroxylase

Question 26

what are the nuclei projections for norepinephrine

Answer 26

locus coeruleus projects to the diencephalon, limbic system, cerebral lobes and cerebellum

Question 27

what are the metabotropic receptors for norepinephrine?

Answer 27

alpha and beta receptors. (1 and 2)

Question 28

alpha 1/beta 1 vs alpha 2/beta 2 for metabotropic receptors of noepinephrine

Answer 28

alpha 1 and beta 1 receptors mediate excitation through the activation of phospholipase C and adenylate cyclase
alpha 2 and beta 2 receptors mediate inhibitory effects by inactivation of adenylate cyclase