| First Author | Stengel PW | Year | 2002 |
| Journal | Am J Physiol Regul Integr Comp Physiol | Volume | 282 |
| Issue | 5 | Pages | R1443-9 |
| PubMed ID | 11959688 | Mgi Jnum | J:113518 |
| Mgi Id | MGI:3686914 | Doi | 10.1152/ajpregu.00486.2001 |
| Citation | Stengel PW, et al. (2002) M(3)-receptor knockout mice: muscarinic receptor function in atria, stomach fundus, urinary bladder, and trachea. Am J Physiol Regul Integr Comp Physiol 282(5):R1443-9 |
| abstractText | Negative chronotropic and smooth muscle contractile responses to the nonselective muscarinic agonist carbamylcholine were compared in isolated tissues from M(3)-muscarinic receptor knockout and wild-type mice. Carbamylcholine (10(-8)-3.0 x 10(-5) M) induced a concentration-dependent decrease in atrial rate that was similar in atria from M(3)-receptor knockout and wild-type mice, indicating that M(3) receptors were not involved in muscarinic receptor-mediated atrial rate decreases. In contrast, the M(3) receptor was a major muscarinic receptor involved in smooth muscle contraction of stomach fundus, urinary bladder, and trachea, although differences existed in the extent of M(3)-receptor involvement among the tissues. Contraction to carbamylcholine was virtually abolished in urinary bladder from M(3)-receptor knockout mice, suggesting that contraction was predominantly due to M(3)-receptor activation. However, approximately 50-60% maximal contraction to carbamylcholine occurred in stomach fundus and trachea from M(3)-receptor knockout mice, indicating that contraction in these tissues was also due to M(2)-receptor activation. High concentrations of carbamylcholine relaxed the stomach fundus from M(3)-receptor knockout mice by M(1)-receptor activation. Thus M(3)-receptor knockout mice provided unambiguous evidence that M(3) receptors 1) play no role in carbamylcholine-induced atrial rate reduction, 2) are the predominant receptor mediating carbamylcholine-induced urinary bladder contractility, and 3) share contractile responsibility with M(2) receptors in mouse stomach fundus and trachea. |
