What important function do peripheral neuronal nicotinic receptors control?

What important function do peripheral neuronal nicotinic receptors control?

• A. Secretion of catecholamines
• B. Muscle contraction
• C. Transmitter release
• D. Heart rate control

Answer: (A)

Peripheral neuronal nicotinic receptors are the fast, ion-channel mediators of autonomic ganglia. Their main job is to translate the arrival of acetylcholine from preganglionic fibers into transmitter release from the postganglionic neuron, which then signals the target organ. When ACh binds these receptors, they open cation channels, depolarize the postganglionic neuron, and trigger the release of its transmitter (norepinephrine in sympathetic pathways or acetylcholine in parasympathetic pathways) to the effector organ. This makes transmitter release the best description of their important function. The other options are not as universally accurate: secretion of catecholamines occurs only in sympathetic terminals, muscle contraction involves the neuromuscular junction receptors, and heart rate is a downstream outcome of the autonomic signal rather than the direct action of these ganglionic receptors.

Peripheral neuronal nicotinic receptors are the fast, ion-channel mediators of autonomic ganglia. Their main job is to translate the arrival of acetylcholine from preganglionic fibers into transmitter release from the postganglionic neuron, which then signals the target organ. When ACh binds these receptors, they open cation channels, depolarize the postganglionic neuron, and trigger the release of its transmitter (norepinephrine in sympathetic pathways or acetylcholine in parasympathetic pathways) to the effector organ. This makes transmitter release the best description of their important function. The other options are not as universally accurate: secretion of catecholamines occurs only in sympathetic terminals, muscle contraction involves the neuromuscular junction receptors, and heart rate is a downstream outcome of the autonomic signal rather than the direct action of these ganglionic receptors.