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) 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 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 Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Kajioka, S. Articles by Brading, A. F Search for Related Content PubMed PubMed Citation Articles by Kajioka, S. Articles by Brading, A. F

Inward current oscillation underlying tonic contraction caused via ET_A receptors in pig detrusor smooth muscle

¹Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom;²Department of Cell Physiology, Nagoya University Graduate School of Medicine, Nagoya 466-8550; and ³Special Care Unit of Dentistry, Faculty of Dentistry, Kyushu University, Fukuoka 812-0012, Japan

Submitted 3 October 2002 ; accepted in final form 28 August 2003

Endothelin-1 (ET-1) is a powerful vasoconstricting peptide. Recent studies showed synthesis of ET-1 and the presence of ET receptors in urinary bladder smooth muscle cells. In the present study, we investigated the possible role of ET-1 in detrusor contraction and its underlying mechanisms in terms of electrical activity. ET-1 caused dose-dependent tonic contraction of bladder smooth muscle strips. Whole cell patch-clamp experiments revealed that ET-1 induced a single transient inward current in the majority of detrusor cells and that additional inward current oscillations were induced in one-third of the cells. The inward current oscillation and tonic contraction shared several characteristic features: 1) both activities lasted for a considerable time after ET-1 washout and 2) only prior application of ET_A receptor antagonists, not ET_B receptor antagonists, significantly suppressed ET-1-induced contractions and the oscillating inward currents. It was concluded that the inward current oscillation underlies ET-1-induced tonic contraction. Experiments with ion substitution and channel blockers suggested that periodic activation of Ca²⁺-activated Cl^- channels caused the oscillating inward currents.

endothelin receptors; urinary bladder

This article has been cited by other articles:

				S. Kajioka, S. Nakayama, H. Asano, and A. F. Brading Involvement of ryanodine receptors in muscarinic receptor-mediated membrane current oscillation in urinary bladder smooth muscle Am J Physiol Cell Physiol, January 1, 2005; 288(1): C100 - C108. [Abstract] [Full Text] [PDF]