Muscarinic receptors play an essential role in regulating thefunctions of organs innervated by the autonomic nervoussystem to maintain homeostasis of the organism. The actionof ACh on muscarinic receptors can result in stimulationor inhibition of the organ system affected. ACh stimulatessecretions from salivary and sweat glands, secretions andcontraction of the gut, and constriction of the airways of therespiratory tract. It inhibits contraction of the heart and relaxessmooth muscle of blood vessels.
