lecture 12 LOs

Question 1

where is ACh a key NT

Answer 1

peripheral and central nervous systems

Question 2

what does ACh do in the peripheral nervous system

Answer 2

used at all neuromuscular junctions and parasympathetic nervous systems

Question 3

what does ACh do in the central nervous system

Answer 3

multiple cell body regions enervate cortical/subcortical regions and the ACh interneurons in the striatum

Question 4

what is ACh made from

Answer 4

choline and acetyl coenzyme A

Question 5

what are the components of ACh catalyzed by

Answer 5

choline and acetyl coenzyme A are catalyzed by choline acetyltransferase (ChAT)

Question 6

where is ChAT found

Answer 6

only in neurons that use Ach

Question 7

what is the rate of ACh synthesis controlled by

Answer 7

avaiability of precursors
rate of cell firing

Question 8

are there selective inhibitors for ChAT

Answer 8

none have been found

Question 9

what packages ACh into vesicles

Answer 9

vesicular ACh transporters (VAChT)

Question 10

what does vesamicol do

Answer 10

blocks VAChT (what packages ACh into vesicles) and reduces ACh levels

Question 11

what does black widow spider venom do

Answer 11

causes massive ACh release in the PNS
cholinergic over activity causes muscle pain, tremors, nausea, vomiting, salivation, copius sweating

Question 12

what does botulinium toxin do to ACh

Answer 12

inhibits its release selectively in nueromuscular joints

Question 13

does ACh undergo direct reuptake

Answer 13

no

Question 14

how are ACh levels controlled

Answer 14

by acetylcholinesterase (AChE)

Question 15

what does AChE do

Answer 15

rapidly breaks down to choline and acetic acid

Question 16

where is AChE found

Answer 16

on post synaptic membranes and in presynaptic cells that metabolize excess ACh

Question 17

what happens to ACh after breakdown

Answer 17

most choline is taken back into the cholinergic nerve terminal by a choline transporter

Question 18

what does hemicholinium-3 (HC-3) do

Answer 18

blocks choline transporters
reduces rate of ACh production

Question 19

what is physostigmine used for

Answer 19

crosses the blood brain barrier
certain types of ACHE-inhibitors are used to offset some of the decline in Alzheimers

Question 20

what is sarin and what does it do

Answer 20

very toxic nerve gas
causes ACh accumulation and overstimulation of cholinergic synapses throughout the CNS and PNS which leads to muscle paralysis and death by asphyxiation

Question 21

what are the two ACh receptor subypes

Answer 21

nicotinic
muscarinic

Question 22

what does the nicotinic ACh receptor subtype respond to, and what type of recepor is it

Answer 22

responds to nicotine agonist
ionotropic

Question 23

what happens in nicotnic ACh receptor when ACh binds

Answer 23

cahnnel opens
Na+ and Ca2+ enter the cell and depolarize the membrane
mediates fast excitatory responses in CNS and PNS

Question 24

how many subunits do nicotinic receptors have

Answer 24

5

Question 25

what does coninuous activation of nicotinic receptors result in

Answer 25

receptors desensitize
channel remains closed even when the agonist is bound
recovers after a short time w no stimulation

Question 26

what does prolonged activation of nicotinic receptors result in

Answer 26

depolarization block
persistent depolarization causes resting potential to be lost
cell cant be excited until agonist is removed and membrane repolarizes

Question 27

what is a nicotinic receptor agonist and what does it do

Answer 27

succinylcholine
muscle relaxant used in some surgical procedures
causes depolarization block

Question 28

what are two nicotonic receptor antagonists and what do they do

Answer 28

mecamylamine: blocks nicotinic receptors both in CNS and autonomic ganglia
d-tubocurarine: blocks muscle nicotinic receptors

Question 29

what do muscarinic receptors respond to

Answer 29

muscarine

Question 30

what types of receptors are muscarinic receptors

Answer 30

metabotropic
operate via second messenger and/or enhance K+ channel opening

Question 31

where are muscarinic receptors found peripherally

Answer 31

caridac and smooth muscle in organs as well as insulin secreting cells of pancreas

Question 32

where are M2 receptors and what do they do

Answer 32

cardiac
slows heart rate when activated
also acts as presynaptic autoreceptor in CNS

Question 33

where are M3 receptors and what do they do

Answer 33

smooth muscle
activation results in conraction (digestive tract), and mediates other sevretory responses (ex salivation)

Question 34

what is a muscarinic agonist

Answer 34

pilocarpine
parasympathomimetic agent
poisioning leads to exaggerated parasympathetic response (SLUDGE): salivation, lacrimation, urination, diarrhea, gastrointestinal distress, and emesis

Question 35

what is a muscarinic antagonist

Answer 35

atopine and scopolamine
inhibit parasympathetic effexts
dialate pupils, redue seretions that clog airways, counteract holinergic poisoning
central effects are drowsiness, euphoria, amnesia, fatigue, dreamless sleep
high does make you: blind as a bat, mad as a hatter, red as a beet, hot as hades, dry as a bone, the bowel and bladded lose their tone, and the heart runs alone

Question 36

what does ACh in the striatum do

Answer 36

regulation of movement depends on balance between ACh and DA

Question 37

what does ACh in the pons do

Answer 37

project to midbrain DA neurons
regulates DA burst firing patterns
mediated by postsynaptic niotinic and muscarinic receptors

Question 38

what does ACh in the basal forebrain cholinergic system (BFCS) do

Answer 38

intermixed with othe transmitters (GABA and glu)
plays a key role in regulating memory and cog functions mediated by forebrain regions, also facilitating attention

Question 39

attention assay for ACh in mice

Answer 39

light flashes, they press L lever, light does not flash they press R lever
if they press the wrong lever its a miss or a false alarm

Question 40

what happens to ACh in frontal cortex in rats performing the attention assay

Answer 40

increased ACh