Question

Which of the following is not a step of action of nerve impulse?

(a) Release of acetylcholine

(b) Production of the muscle action potential

(c) Termination of acetylcholine

(d) Guanosine monophosphate to guanine

I had been asked this question in an interview.

My question is from Clinical Significance of 5′ topic in chapter Clinical Enzymology of Enzyme Technology

Answer 1

The correct answer is (d) Guanosine monophosphate to guanine

For explanation: “Guanosine monophosphate to guanine.” This is a part of the pathway of purine degradation by 5^I – nucleotidase. Steps involved in action of nerve impulse are:

• Release of acetylcholine during exocytosis into the synaptic cleft.

• Activation of acetylcholine receptor by binding of 2 molecules of released acetylcholine which opens the channels of small cations such as Na^+.

• Production of muscle action potential due to inflow positively charged sodium ions.

• Termination of acetylcholine by acetylcholine esterase which is attached to collagen fiber in extracellular matrix of synaptic cleft.