What does M3R stand for?

[FIGURE 3 OMITTED] [FIGURE 4 OMITTED] An important role of parasympathetic cholinergic neurons and postsynaptic muscarinic acetylcholine receptors in the contraction of gastric smooth muscle has been provided in functional studies (Makhlouf and Murthy, 2006).

Muscarinic acetylcholine receptor subtypes in cerebral cortex and hippocampus.

[FIGURE 5 OMITTED] [FIGURE 6 OMITTED] The present study further investigated the potential involvement of muscarinic acetylcholine receptors.

Environmental Protection Agency (Research Triangle Park, NC, USA); imechine (Latoxan, Valence, France), a hydrophilic antagonist of neuronal nicotinic acetylcholine receptors (nAChR), and the noncompetitive antagonist QX-222 (Astra Pharmaceuticals, Westborough, MA, USA) (both at 20 mM in distilled water); atropine sulfate (RBI, Natick, MA, USA), a muscarinic acetylcholine receptor antagonist (40 mM in distilled water); 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), an inhibitor of protein kinase (PK) C, and N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA-1004), an inhibitor of PKA (both from RBI, and each at 20 mM in distilled water).

Reconstitution of the muscarinic acetylcholine receptor.