Table 3.

Semiquantitative localization of muscarinic acetylcholine receptor (mAChR) subtypes (M₁–M₅) in various tissues of mice

Tissues	Loss of mAChR sites in muscarinic knockout mice	mRNA expression	Antibody binding
Submandibular gland	M3 > M2	M3 (Shida et al., 1993)	M3 (42%), M1 (36%), M2 (12%), M2 (7%) (Dörje et al. 1991)
		M1, M3 (Gautam et al., 2004)
Sublingual gland	M3
Lung	M2 > M3, M5	M1, M2, M3 (Struckmann et al., 2003)	M4 (41%), M2 (40%) (Dörje et al., 1991)
Heart	M2	M2 (Maeda et al., 1988)	M2 (88%) (Krejčí and Tuček, 2002)
		M2 (Peralta et al., 1987)
		M2 (Levey, 1993)
		M2 (>90%) (Krejčí and Tuček, 2002)
Stomach	M2	M1–M5 (Aihara et al., 2005)
Pancreas	M3 > M2, M4	M4 (Peralta et al., 1987)
		M1, M3 (Boschero et al., 1995)
Ileum	M2 > M3		M2 (69%), M4 (12%), M3 (4%), M1 (3%) (Dörje et al., 1991)
			M2, M4 (Takeuchi et al., 2002)
Colon	M2
Bladder	M2 > M3, M4, M5	M2, M3 (Maeda et al., 1988)	M1–M5 (Giglio et al., 2005)
Prostate	M1 > M3	M3 (Kim et al., 2005)	M2 (Ruggieri et al., 1995)
			M2, M3 (Pontari et al., 1998)
			M1 (>70%) (Ruggieri et al., 1995)

The rank order is based on the loss of [N-methyl-³H]scopolamine methyl chloride ([³H]NMS)-binding sites measured in each single muscarinic receptor knockout mice (M₁–M₅), in comparison with wild type, as shown in Table 1. The distribution of mRNA and antibody binding was taken from the references shown.