What is the name of the cholinergic neurotransmitter?
A. acetylcholinesterase
B. epinephrine
C. norepinephrine
D. acetylcholine
The correct answer and explanation is:
The correct answer is D. acetylcholine.
Acetylcholine is the primary cholinergic neurotransmitter. It plays a crucial role in both the central and peripheral nervous systems. In the peripheral nervous system, acetylcholine is involved in transmitting nerve impulses to muscles, making it essential for muscle contraction. This is particularly important in the somatic nervous system, where acetylcholine is the neurotransmitter used at neuromuscular junctions to initiate muscle movement.
In the central nervous system, acetylcholine is involved in a variety of functions, including memory, learning, and attention. It is released by cholinergic neurons in areas like the hippocampus and cortex, which are critical for cognitive processes. In fact, acetylcholine’s involvement in learning and memory is one reason why diseases such as Alzheimer’s disease, which are characterized by a loss of cholinergic neurons, result in cognitive decline.
Acetylcholine is synthesized from choline and acetyl-CoA and is broken down in the synaptic cleft by the enzyme acetylcholinesterase. The rapid breakdown of acetylcholine after its release is important to prevent continuous stimulation of the postsynaptic cell. This breakdown ensures that the signal transmission is brief and that the synapse is ready for the next neurotransmission event.
The other options listed in the question do not refer to cholinergic neurotransmitters:
- A. acetylcholinesterase is the enzyme that breaks down acetylcholine.
- B. epinephrine and C. norepinephrine are adrenergic neurotransmitters, primarily involved in the sympathetic nervous system’s “fight or flight” response.