HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/4/F703    most recent 00162.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Stanton, M. C. Articles by Moreland, R. S. Search for Related Content PubMed PubMed Citation Articles by Stanton, M. C. Articles by Moreland, R. S.

Partial bladder outlet obstruction alters Ca²⁺ sensitivity of force, but not of MLC phosphorylation, in bladder smooth muscle

¹Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia 19102; ²Department of Urology, The Children's Hospital of Philadelphia, Philadelphia 19101; and ³Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania 19101

Submitted 21 May 2003 ; accepted in final form 4 June 2003

Partial bladder outlet obstruction in the rabbit produces changes in bladder function similar to those seen clinically in patients with obstructive uropathies. Whole organ function is significantly altered, as are the smooth muscle cells inside the bladder wall. This study was designed to determine whether outlet obstruction alters smooth muscle function at the level of contractile filaments. Rabbit bladders were partially obstructed for 2 wk. Triton X-100 was used to provide a detergent-skinned bladder smooth muscle preparation that would allow control of the intracellular environment while the ability to shorten and develop force is maintained. Ca²⁺-force and Ca²⁺-myosin light chain (MLC) phosphorylation relations and maximal velocity of shortening were determined. The Ca²⁺ sensitivity of force was significantly lower in tissues from animals subjected to outlet obstruction compared with tissues from control animals. In contrast, no difference was noted in the Ca²⁺ sensitivity of MLC phosphorylation. Maximal levels of stress and MLC phosphorylation were similar in both animal groups. Maximal velocity of shortening was significantly slower in tissues from outlet-obstructed animals at all Ca²⁺ concentrations compared with tissues from control animals. Ultrastructurally, detergent skinning had little effect on structural integrity. Moreover, tissues from obstructed animals showed an increase in the number of sarcolemmal attachment plaque structures. We suggest that partial bladder outlet obstruction produces deleterious (e.g., decrease in Ca²⁺ sensitivity of force) and compensatory (e.g., increase in membrane attachment plaques) changes in bladder smooth muscle cells.

maximal velocity of shortening; Triton X-100 detergent-skinned fibers; attachment plaques; electron micrographs

This article has been cited by other articles:

				A. F. Martin, S. Bhatti, G. J. Pyne-Geithman, M. Farjah, V. Manaves, L. Walker, R. Franks, A. R. Strauch, and R. J. Paul Expression and function of COOH-terminal myosin heavy chain isoforms in mouse smooth muscle Am J Physiol Cell Physiol, July 1, 2007; 293(1): C238 - C245. [Abstract] [Full Text] [PDF]

				M. C. Stanton, D. Delaney, S. A. Zderic, and R. S. Moreland Partial bladder outlet obstruction abolishes the receptor- and G protein-dependent increase in calcium sensitivity in rabbit bladder smooth muscle Am J Physiol Renal Physiol, October 1, 2004; 287(4): F682 - F689. [Abstract] [Full Text] [PDF]