lecture 3

Question 1

ionotropic receptors are also known as ___________. include examples and time scale

Answer 1

ligand gated channels; nicotinic, ACh receptors, GABA, glutamate receptors; milliseconds b/c transmitter binds outside and causes conformational change –> hyperpolarization/depol –> cellular effects

Question 2

metabotropic receptors are also known as __________. include exmaples and time scale

Answer 2

G-protein coupled receptors; muscarinic, ACh receptor; seconds b/c second messengers can activate stuff like effectors, calcium release, protein phosphorylation, etc.. –> cellular effects

Question 3

what receptors take minutes? hours?

Answer 3

kinase linked receptors; nuclear receptors

Question 4

What is the story of Opechancanough?

Question 5

physostigmine vs tubocurare

Answer 5

tubocurare - bind to same receptor as acetylcholine, stop channel from opening (non-depolarizing blocking agents)

Question 6

nerve agents are a class of _______ that block __________, an enzyme that normally destroys acetylcholine

Answer 6

organophosphates; acetylcholinesterase

Question 7

too much acetylcholine can lead to

Answer 7

flaccid paralysis

Question 8

toxic reactions of muscarinic receptors due to nerve gases

Answer 8

DUMBELL - diarrhea, urination, miosis, bronchoconstriction/bradycardia, emesis, lacrimation, loss of muscle strength

Question 9

excitation-contraction coupling is the…

Answer 9

rapid communication btwn electrical events occurring in the plasma membrane of skeletal muscle fibres and Ca2+ release from the SR, which leads to contraction

Question 10

ACh at the NMJ are exclusively nicotinic or muscarinic?

Answer 10

nicotinic

Question 11

molecular machines governing exocytosis of synaptic vesicles

Answer 11

SNARE complex (synaptobrevin, syntaxin, Snap25)

Question 12

botulinim toxin

Answer 12

proteases that chop up the SNARE complex! work by inhibiting the release of GABA therefore leading to more excitation in the tissue and yeah – “sausage poison” bc it’s from raw meat or heroin– muscle weakness, breathing difficulties, paralysis, death – BTX-A is the cosmetic botox

Question 13

nicotinic receptor structure has how many subunits

Answer 13

5, each composed of a transmembrane protein that has 4 membrane spanning alpha helical regions (m1, m2, m3, m4)

Question 14

what is an example of a toxin that stops acetylcholine from binding

Answer 14

bungarotoxin, snake toxin

Question 15

acetylcholine does what

Answer 15

depolarize cell and cause muscle contraction

Question 16

why does continuous end plate depol cause muscle relaxation?

Answer 16

bc sodium channels rapidly inactivate, making it harder to repolarize (so depolarizing blocking agents can essentially act like nondepolarizing muscle relaxants) — in other words nicotinic receptors are basically desensitized

Question 17

TOF phenomenon

Answer 17

if you give enough blocking agent (neuromuscular blockers on pre and postsyanptic nAChRs) you get a specific pulse

Question 18

less acetylcholine in hippocampus is an effect of which brain disease

Answer 18

alzheimers

Question 19

LTP, which promotes learning, is associated with which neurotransmitter

Answer 19

acetylcholine

Question 20

alzheimers cholinergic hypothesis

Answer 20

caused by reduced acetylcholine

Question 21

alzheimers drugs for early stages

Answer 21

aricept (donepezil), exelon (riavastigamine)

Question 22

alzheimers due to what in the brain

Answer 22

amyloid plaques - neurofibrillary tangles of the tau protein – loss of synapses and neurons in hippocampus and entorhinal cortex

Question 23

stigmines inhibit what

Answer 23

acetylcholinesterases