Abstract
Adiponectin is an adipose tissue–secreted protein and is a multifunctional adipocytokine. However, the association of adiponectin with bladder contraction has not been investigated. In this study, the adiponectin-sense transgenic mouse (Adip-Sen mouse; age, 16–24 weeks; male) and age-matched controls (C57Bl mouse) were studied. The Adip-Sen mouse showed a significant increase in plasma adiponectin levels (56.2%; P < 0.01), compared with those in the C57Bl mouse, without affecting other lipid parameters. Isometric force development in bladder smooth muscle tissues were detected using an organ-bath system. Although carbachol (CCh)–induced (0.1–100 µM) time- and dose-dependent contractions in Adip-Sen mouse bladder were slightly enhanced, compared with those in the C57Bl mouse during a low range (0.3–1.0 µM) of CCh, differences could not be detected with other CCh concentrations. However, the reduction in contraction under Ca2+-replaced conditions was significantly different between Adip-Sen and C57Bl mice (94.1 and 66.3% of normal contraction, respectively; n = 5). A parameter of Ca2+ sensitivity, the relation between intracellular Ca2+ concentration and contraction, was increased in the Adip-Sen mouse, compared with that in the C57B1 mouse. This Ca2+ dependency in the Adip-Sen mouse was reduced by a protein kinase C (PKC) inhibitor, but not by a Rho kinase inhibitor. Expression of the calcium-dependent isoform of PKC, PKCα, was increased in the Adip-Sen mouse bladder, and CCh-induced phosphorylation of PKCα was also enhanced, compared with those in the C57Bl mouse. In conclusion, adiponectin is associated with bladder smooth muscle contraction, which involves an increase in Ca2+ dependency of contraction mediated by PKCα expression.
Footnotes
- Received November 19, 2012.
- Accepted January 29, 2013.
This study was supported by a Grant-in-Aid for Encouragement of Young Scientists from the Ministry of Education, Culture, Sports, Science and Technology (MEXT; 21590290) in Japan; and a Private University High Technology Research Center Project matching fund subsidy from MEXT (NEXT; S1001011).
- Copyright © 2013 by The American Society for Pharmacology and Experimental Therapeutics
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