|
|
||||||||
Departments of 1 Urology and
3 Pharmacology,
Subtype-selective muscarinic antagonists effects on carbachol-induced and electric field-stimulated contractility of rat bladder were compared in vitro. Schild plot analysis of cumulative carbachol dose-response curves in the presence of antagonists was consistent with M3-mediated bladder contractions. However, nerve-evoked contractions were inhibited 15% at 30 Hz (P < 0.01) by 10 nM pirenzepine (M1-selective antagonist), whereas 10 nM methoctramine (M2-selective antagonist) increased these contractions by 17% at 30 Hz (P < 0.01). Identical doses had no effect on carbachol-induced contractions, indicating prejunctional M1 facilitory and M2 inhibitory receptors. m1 Receptors could not be identified by subtype-selective antibodies, nor could the m1 transcript be identified by Northern hybridization. However, m1, m2, m3, and m4 transcripts were identified in rat bladder using the reverse transcriptase-polymerase chain reaction, providing support for the existence of the m1 subtype. In conclusion, strong evidence is provided for the existence of prejunctional M1 facilitory and M2 inhibitory and postjunctional M3 receptors modulating contractility in the rat urinary bladder.
smooth muscle; reverse transcriptase-polymerase chain reaction; acetylcholine
This article has been cited by other articles:
![]() |
M. A. Pontari, A. S. Braverman, and M. R. Ruggieri Sr. The M2 muscarinic receptor mediates in vitro bladder contractions from patients with neurogenic bladder dysfunction Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2004; 286(5): R874 - R880. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. S. Braverman and M. R. Ruggieri Sr. Hypertrophy changes the muscarinic receptor subtype mediating bladder contraction from M3 toward M2 Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2003; 285(3): R701 - R708. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. P. Parkman, A. P. Pagano, and J. P. Ryan Subtypes of muscarinic receptors regulating gallbladder cholinergic contractions Am J Physiol Gastrointest Liver Physiol, May 1, 1999; 276(5): G1243 - G1250. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. S. Braverman, G. R. Luthin, and M. R. Ruggieri M2 muscarinic receptor contributes to contraction of the denervated rat urinary bladder Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1998; 275(5): R1654 - R1660. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |