Muscarinic Receptor Antagonist Explorer Kit

The action of the neurotransmitter acetylcholine (ACh) is mediated through two types of receptors; ionotrophic nicotinic receptors and metabotrophic muscarinic receptors. The muscarinic receptors belong to the superfamily of 7-transmembrane G-protein coupled receptors. Five subtypes of muscarinic receptors have been cloned and named m1-m5.^1-2

The muscarinic receptors are widely distributed throughout the body, but are predominantly expressed within the parasympathetic nervous system and exert both excitatory and inhibitory control over central and peripheral tissues.^1-2

Muscarinic receptors participate in a number of physiological functions such as regulation of heart rate, muscle contraction, cognition, sensory processing and motor control.¹ They also participate in learning and memory processing.^3-4 The m1 receptors are the most abundant muscarinic subtype in the cortex and striatum. m1 receptors were also localized in the myenteric plexus where they function as autoreceptors to enhance the release of Ach from the nerves.^5-6