|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Articles in PresS, published online ahead of print June 6, 2002
Am J Physiol Regu Physiol, 10.1152/ajpregu.00116.2002
Submitted on February 20, 2002
Accepted on May 31, 2002
1 Department of Urology, Temple University School of Medicine, Philadelphia, PA, USA
2 Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA
3 Department of Urology, Temple University School of Medicine, Philadelphia, PA, USA; Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA
* To whom correspondence should be addressed. E-mail: rugg1{at}msn.com.
M3 muscarinic receptors mediate cholinergic induced contraction in most smooth muscles. However, in the denervated rat bladder, M2 receptors participate in contraction, since M3-selective antagonists (p-F-HHSiD and 4-DAMP) have low affinities. However, the affinity of the M2-selective antagonist, methoctramine in the denervated bladder is consistent with M3 receptor mediating contraction. It is possible that two pathways interact to mediate contraction; one mediated by the M2 receptor and one by the M3. To determine whether an interaction exists, the inhibitory potencies of combinations of methoctramine and p-F-HHSiD for reversing cholinergic contractions were measured. In normal bladders, all combinations gave simple additive effects. In denervated bladders, synergistic effects were seen with the 10:1 and 1:1 (methoctramine:p-F-HHSiD w/w) combinations. Following application of the sarcoplasmic reticulum ATPase inhibitor thapsigargin to normal tissue, the 10:1 and 1:1 ratios became synergistic, mimicking denervated tissue. Thus in normal bladders both M2 and M3 receptors can induce contraction. In the denervated bladder, the M2 and the M3 receptor interact in a facilitatory manner to mediate contraction.
This article has been cited by other articles:
![]() |
A. S. Braverman, R. J. Tallarida, and M. R. Ruggieri Sr. The Use of Occupation Isoboles for Analysis of a Response Mediated by Two Receptors: M2 and M3 Muscarinic Receptor Subtype-Induced Mouse Stomach Contractions J. Pharmacol. Exp. Ther., June 1, 2008; 325(3): 954 - 960. [Abstract] [Full Text] [PDF] |
||||
![]() |
K.-E. Andersson and A. J. Wein Pharmacology of the Lower Urinary Tract: Basis for Current and Future Treatments of Urinary Incontinence Pharmacol. Rev., December 1, 2004; 56(4): 581 - 631. [Abstract] [Full Text] [PDF] |
||||
![]() |
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] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |