Cholinergic Transmission

Question 1

what was the first neurotransmitter discovered?

Answer 1

acetylcholine

Question 2

in which pathways is ACh implemented?

Answer 2

cholinergic pathways

Question 3

within the peripheral nervous system, which three systems contain cholinergic pathways?

Answer 3

neuromuscular junctions/ somatic motor system (including motor nerve and skeletal muscle)
and in the autonomous nervous system: the parasympathetic system and the sympathetic system

Question 4

what is the difference between the sympathetic and the parasympathetic nervous systems?

Answer 4

parasympathetic:
stimulating actions for ‘rest and digest’ or ‘feed and breed’
sympathetic:
responsible for stimulating fight-or-flight actions.

Question 5

what are the three major locations of cholinergic pathways in the central nervous system?

Answer 5

1. interneuron within the striatum
2. basal forebrain cholinergic system.
3. dorsolateral pons.

Question 6

what is the ChAT enzyme?

Answer 6

controls the synthesis rate of acetylcholine and coA via controlling precursor availability and neuronal firing

Question 7

what is the AChE enzyme?

Answer 7

controls the breakdown of Ach
located inside presynaptic terminal to breakdown excess acetylcholine and located on the postsynaptic membrane to provide transmission remportal and spatial precision

Question 8

what are six AChE blockers?

Answer 8

physostigmine
neostigmine 
pyridostigmine
sarin and soman
novichok 
black widow spider venok

Question 9

describe the AChE blocker physostigmine..

Answer 9

comes from clabar bean seeds and can cross over the BBB

this blocker causes poisoning and induces symptoms such as mental confusion and slurred speech

Question 10

describe the AChE blockers neostigmine and pyridostigmine…

Answer 10

also known as prostigmin and mestinon
these blockers are synthetic and do not cross the BBB
these blockers can be used to treat myasthenia gravis (a weakness of the muscles disease)

Question 11

describe the AChE blockers sarin and soman…

Answer 11

these blockers are nerve gases which can cross the BBB.
they produce irreversible outcomes and induce many symptoms including over stimulation of the Ach systems and vomiting.
there is however, an antidote called pyridostigmine

Question 12

describe the AChE blocker Novichok…

Answer 12

novichok is a secret chemical weapon that is extremely potent and irreversible. novichok can also cross the BBB

Question 13

what disease can AChE inhibitors be used to treat?

Answer 13

alzheimers as they can prevent the breakdown of Ach which is a common contributer to the disease

Question 14

what is the enzyme VAChT?

Answer 14

vesicular acetycholine transporter
located at the presynaptic terminal
packages ach into vesicles for secretion

Question 15

what is VAChT blocker?

Answer 15

versamicol

Question 16

what are choline transporters?

Answer 16

choline transporters sustain ach synthesis via recylcing choline. they are located in the presynaptic terminal

Question 17

what are two major cholinergic receptor pathways?

Answer 17

nicotinic and muscarinic

Question 18

what is the distribution of nicotinic receptors?

Answer 18

located in the neuro-muscular junctions, the autonomous systems and the central nervous system.

Question 19

what are the physiological effects of the cholinergic pathways in the NMJs, autonomous systems, and the CNS?

Answer 19

NMJs: muscle contraction, breathing, movements.
autonomous systems: activation of nachrs in autonomic ganglia, stimualte adrenaline release, increase metabolic rate.
CNS: influence mood, cognition, and reinforcing effects.

Question 20

what are four agonists of nAChRs?

Answer 20

nicotine
varenicline tartrate
galantamine hydrobromide
succinylcholine

Question 21

what are the three categories of nAChR antagonists and their sub-antagonists?

Answer 21

ganglion blockers: mecamylamine (inversine)
neuromuscular blockers: D-tubocurarine, vecuronium, pancuronium, atracurium, and snake toxins.
centrally acting nicotinic antagonists: dextromethophan

Question 22

describe the distribution of muscarinic receptor subtypes in the peripheral nervous system…

Answer 22

M2Rs: cardiac muscle
M3Rs: smooth muscle cells, beta-cells of pancreas, mediation of other secretory processes

Question 23

describe the distribution of muscarinic receptors in the central nervous system…

Answer 23

receptors widely distributed throughout the brain, especially M5 receptors.

Question 24

what are muscarinic receptor agonists?

Answer 24

parasympathetic agents: muscarine, pilocarpine, arecoline

Question 25

what are muscarinic receptor antagonist?

Answer 25

atropine and scopolamine