help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS

Biophysical Journal 51: 895-904 (1987)
© 1987 the Biophysical Society

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Barr, L
Right arrow Articles by Gu, F J
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barr, L
Right arrow Articles by Gu, F J

A quantitative model of myosin phosphorylation and the photomechanical response of the isolated sphincter pupillae of the frog iris.

L Barr and F J Gu

ABSTRACT

The time courses of isometrically recorded photomechanical responses of isolated sphincter pupillae of Rana pipiens can be accurately predicted by a set of differential equations derived from phosphorylation theory of smooth muscle contraction. We compared actual light-stimulated contractions with calculated ones over a wide range of stimulus intensities (56-fold) and durations (0.4-4.0 s). The hypothetical Ca++-calmodulin-myosin light chain kinase cascade acts as a "valve" to control the flow of ATP through a phosphorylation-dephosphorylation cycle. When the rate of flow of ATP through the phosphorylation-dephosphorylation cycle is increased, the percentage of phosphorylated myosin increases. The time courses of the concentrations of phosphorylated myosin during different responses are seen to be functions of the time courses of the opening and closing of the coupling cascade "valve." The calculations predict experimentally measurable intermediate variables, which can aid the investigation of the application of quantitative phosphorylation theory to amphibian sphincter pupillae and to smooth muscle in general.




This article has been cited by other articles:


Home page
 Am. J. Physiol. Cell Physiol.Home page
A. P. Krivoshik and L. Barr
Force relaxes before the fall of cytosolic calcium in the photomechanical response of rat sphincter pupillae
Am J Physiol Cell Physiol, July 1, 2000; 279(1): C274 - C280.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1987 by the Biophysical Society.