Question

Which of the following statements regarding neurotransmitters is TRUE?

A) Acetylcholine is broken down by enzymes present on postsynaptic cell membranes.
B) Acetylcholine that is released at synapses binds to adrenergic receptors in the postsynaptic cell membrane.
C) Catecholamines are the most abundant neurotransmitters in the central nervous system.
D) Opiate drugs,such as morphine,are antagonists of a class of neurotransmitters called endorphins.
E) Gamma-aminobutyric acid (GABA)is a major excitatory transmitter in the central nervous system.

Answer 1

The true statement about neurotransmitters is A) Acetylcholine is broken down by enzymes present on postsynaptic cell membranes, specifically by the enzyme acetylcholinesterase.

Step-by-step explanation:

The correct statement regarding neurotransmitters is A) Acetylcholine is broken down by enzymes present on postsynaptic cell membranes. Acetylcholine (ACh) is a neurotransmitter that functions at the neuromuscular junction and in various areas within the nervous system. Once ACh is released into the synaptic cleft, it is degraded by the enzyme acetylcholinesterase, which is located on the postsynaptic membranes. This degradation process is necessary for the postsynaptic cell to 'reset' and be ready for the next signal.

As for the other choices: B) Acetylcholine binds to cholinergic receptors, not adrenergic. C) Catecholamines are not the most abundant neurotransmitters in the central nervous system. D) Opiate drugs are agonists, not antagonists of endorphins. E) GABA is a major inhibitory transmitter, not excitatory, in the central nervous system.