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Neurotransmitters: Acetylcholine

NEURO-GKRWPZ

Acetylcholine (Ach) was the first neurotransmitter to be identified. It functions both in the peripheral nervous system and in the central nervous system.

Based on what you know about the history and the effect of acetylcholine, which of the following statements is FALSE?

A

German physiologist Otto Loewi first confirmed Ach as a neurotransmitter, which he initially named Vagusstoff (vagus substance) because Ach was released by the vagus nerve.

B

To prove that some chemical agent is at play to transfer electrical information, Otto Loewi stimulated the vagus nerve of a frog heart and transferred the perfusate from the stimulated heart to a second heart. Containing Ach released from the vagus nerve, the perfusate slows the beating of the second heart although its own vagus nerve had not been stimulated.

C

Ach has an inhibitory effect on heart muscles, slowing down the heart-​beat. On the other hand, Ach has an excitatory effect on skeletal muscles, activating voluntary movements.

D

Nicotinic acetylcholine receptors and muscarinic acetylcholine receptors are the reasons why Ach has differentiating effects on heart muscles and skeletal muscles. Muscarinic acetylcholine receptors are present on the surface of skeletal muscle cells, and nicotinic acetylcholine receptors are present on heart muscle cells.