The influence of changes in extracellular and intracellular sodium concentration on detrusor contractility

BJU International
Dler BesaraniC H Fry

Abstract

To determine the role of Na+-Ca2+ exchange in the regulation of isolated detrusor smooth muscle contractility. Isolated guinea-pig detrusor strips were used to record isometric tension generated by; (a) electrical-field stimulation to elicit nerve-mediated responses; and (b) adding carbachol or superfusing with a high-K+ solution. The [Na+] gradient between extracellular and intracellular compartments was altered by: (i) reducing superfusate [Na+] in stages from 140.2 to 10.2 mm; (ii) addition of the cardiac glycoside strophanthidin (200 microm). RESULTS Reducing extracellular [Na+] reversibly reduced the magnitude of nerve-mediated contractions but increased the resting tension and magnitude of carbachol-induced contracture. The mean (sd) [Na+] required for a half-maximum effect on attenuating contractions, at 85.9 (6.2) mm, and developing contracture, at 59.1 (14.3) mm, were significantly different. The time constants of changes to nerve-mediated contractions and carbachol contracture were also significantly different, at 147 (5) vs 1207 (386) s, respectively. These differences suggest that separate mechanisms influence nerve-mediated contraction and contracture in low-Na+ solutions. Exposure to the cardiac glycoside strophan...Continue Reading

References

Mar 1, 1985·The American Journal of Physiology·D A Eisner, W J Lederer
Apr 15, 1996·Annals of the New York Academy of Sciences·D M BersR A Bassani
Jan 1, 1996·Neurourology and Urodynamics·R M LevinA J Wein
Mar 4, 1997·Proceedings of the National Academy of Sciences of the United States of America·M Juhaszova, M P Blaustein
Jan 3, 2001·American Journal of Physiology. Renal Physiology·F SchwedaA Kurtz
Apr 5, 2001·American Journal of Physiology. Cell Physiology·C Wu, C H Fry

❮ Previous
Next ❯

Citations

Feb 23, 2010·Journal of Pharmacological Sciences·Hidemichi MurataYuji Imaizumi

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cardiac Glycosides

Cardiac glycosides are a diverse family of naturally derived compounds that bind to and inhibit na+/k+-atpase. Discover the latest research on cardiac glycosides heres.