Question

Differentiate between nicotinic and muscarinic acetylcholine receptors and identify where they are found in the body

A) Nicotinic receptors are found in smooth muscle, while muscarinic receptors are in skeletal muscle
B) Nicotinic receptors are found in the CNS, while muscarinic receptors are in the PNS
C) Nicotinic receptors are ionotropic, while muscarinic receptors are metabotropic
D) Muscarinic receptors are found in the neuromuscular junction, while nicotinic receptors are in the autonomic ganglia

Answer 1

Nicotinic receptors are ionotropic, ligand-gated channels found at the NMJ and autonomic ganglia, while muscarinic receptors are metabotropic, G protein-coupled receptors found in various parasympathetic and sympathetic target organs.

Step-by-step explanation:

The cholinergic system includes two primary types of acetylcholine receptors: nicotinic receptors and muscarinic receptors. These receptors are differentiated based on their mechanism of action and their binding specificity.

Nicotinic receptors are ionotropic, meaning they are ligand-gated ion channels that lead to rapid depolarization of the postsynaptic cell. These receptors are present at the neuromuscular junction (NMJ) and in autonomic ganglia. On the other hand, muscarinic receptors are metabotropic, which are G protein-coupled receptors that have more prolonged effects on cells and can either depolarize or hyperpolarize the target cell.

They are primarily found in parasympathetic target organs, such as the heart, smooth muscle, and glands, and in some sympathetic target structures such as sweat glands and blood vessels in skeletal muscles.