Cevimeline hydrochloride works by activating which receptor to stimulate salivary secretion?

• A. M3 receptors
• B. M2 receptors
• C. Nicotinic receptors
• D. Dopamine receptors

Answer: (A)

Salivary secretion is driven by muscarinic receptor activation on salivary gland cells, especially the M3 subtype. Cevimeline hydrochloride is a muscarinic receptor agonist that preferentially stimulates M3 receptors on the glands. Activation of M3 triggers the Gq-PLC-IP3 pathway, raising intracellular calcium and triggering exocytosis of saliva from acinar and ductal cells. M2 receptors are mainly involved in regulating heart rate and have less a direct role in glandular secretion. Nicotinic receptors are ion channels found at autonomic ganglia and neuromuscular junctions, not the primary pathway for inducing saliva. Dopamine receptors are not part of this mechanism. Therefore, the receptor responsible for cevimeline’s effect on salivary secretion is the M3 muscarinic receptor.