Obstruction of the urethra results in numerous alterations in the urinary bladder that impair both its storage and emptying properties. The detailed molecular mechanisms responsible for these changes in function associated with obstruction-induced remodeling have not been clearly delineated. This research project is based upon the hypothesis that the depression function of the obstructed bladder is the result of alterations in both excitation-contraction coupling (Ca2+-availability) and the contractile apparatus (Ca2+-dependent activity) in detrusor muscle. To test this hypothesis, the following specific aims will be addressed using strips of detrusor muscle obtained from normal, decompensated, and compensated rabbit bladder.
Aim 1 : To correlate the force-velocity-length relations of intact and skinned detrusor muscle associated with bladder obstruction and its reversal.
This aim will determine the mechanism of altered active and passive mechanics at the tissue, cell and cross- bridge level. Chemically skinned muscle strips will allow for the precise and direct control of the environment surrounding the contractile apparatus, bypassing the normal excitation-contraction pathway.
Aim 2 : To determine the relationship among agonist concentration, cytoplasmic (Ca2+) and the time course of contraction. Laser photolysis of caged-compounds will be used to initiate contraction while monitoring the intracellular (Ca2+) with Indo-1.
This aim will determine if the altered contractility is due to altered calcium mobilization.
Aim 3 : To determine the time course of myosin light chain phosphorylation, (Ca2+) and isometric force in intact and myosin light chain phosphorylation, actin-activated myosin ATPase activity and isometric force in permeabilized tissues during various stimuli.
This aim will test for alterations in the coupling of the Ca2+ signal to contractile activation.
Aim 4 : To determine the significance of other regulatory signaling pathways. The protein kinase C, mitogen-activated protein kinase, calesmon phosphorylation cascade will be measured.
This aim will determine if the loss of maintained contractile force in the decompensated bladder is due to alterations in steps important in thin filament regulation. The results of these studies will elucidate the specific steps of excitation-contraction coupling that are associated with bladder dysfunction. Moreover, the results of these studies will also determine which alterations in contractile or regulatory proteins are associated with bladder remodeling and will provide a more complete understanding of the cellular and molecular mechanisms responsible for the depressed bladder function associated with outlet obstruction.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK057252-03
Application #
6350749
Study Section
Special Emphasis Panel (ZRG4-UROL (01))
Program Officer
Mullins, Christopher V
Project Start
1999-05-01
Project End
2004-01-31
Budget Start
2001-02-01
Budget End
2002-01-31
Support Year
3
Fiscal Year
2001
Total Cost
$225,897
Indirect Cost
Name
Mcp Hahnemann University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
City
Philadelphia
State
PA
Country
United States
Zip Code
19102
Basha, Maureen E; Chang, Shaohua; Burrows, Lara J et al. (2013) Effect of estrogen on molecular and functional characteristics of the rodent vaginal muscularis. J Sex Med 10:1219-30
Wang, Tanchun; Kendig, Derek M; Chang, Shaohua et al. (2012) Bladder smooth muscle organ culture preparation maintains the contractile phenotype. Am J Physiol Renal Physiol 303:F1382-97
Wang, Tanchun; Kendig, Derek M; Smolock, Elaine M et al. (2009) Carbachol-induced rabbit bladder smooth muscle contraction: roles of protein kinase C and Rho kinase. Am J Physiol Renal Physiol 297:F1534-42
Singh, Kamaljit; Arora, Divya; Poremsky, Elizabeth et al. (2009) N1-Alkylated 3,4-dihydropyrimidine-2(1H)-ones: Convenient one-pot selective synthesis and evaluation of their calcium channel blocking activity. Eur J Med Chem 44:1997-2001
Smolock, Elaine M; Wang, Tanchun; Nolt, Jocelyn K et al. (2007) siRNA knock down of casein kinase 2 increases force and cross-bridge cycling rates in vascular smooth muscle. Am J Physiol Cell Physiol 292:C876-85
Stanton, Michaela C; Austin, J Christopher; Delaney, Daniel P et al. (2006) Partial bladder outlet obstruction selectively abolishes protein kinase C induced contraction of rabbit detrusor smooth muscle. J Urol 176:2716-21
Christ, George J; Liebert, Monica (2005) Proceedings of the Baltimore smooth muscle meeting: identifying research frontiers and priorities for the lower urinary tract. J Urol 173:1406-9
Stanton, Michaela C; Delaney, Daniel; Zderic, Stephen A et al. (2004) 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 287:F682-9
Su, Xiaoling; Smolock, Elaine M; Marcel, Kristi N et al. (2004) Phosphatidylinositol 3-kinase modulates vascular smooth muscle contraction by calcium and myosin light chain phosphorylation-independent and -dependent pathways. Am J Physiol Heart Circ Physiol 286:H657-66
Gorenne, Isabelle; Su, Xiaoling; Moreland, Robert S (2004) Caldesmon phosphorylation is catalyzed by two kinases in permeabilized and intact vascular smooth muscle. J Cell Physiol 198:461-9

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