Net and radioactive calcium movements were studied in the rat uterus during stimulation with acetylcholine and high potassium solutions. High potassium did not affect the efflux of intracellular Ca45, but was able to release Ca45 from a small parallel Ca fraction which was believed to be located in the cell membranes. High potassium did markedly slow the influx of Ca45 and caused a net calcium efflux. Acetylcholine had no effect on calcium movements in polarized myometrium, but it increased the Ca45 influx in depolarized uteri. Ca45 taken up during contraction exchanged more slowly during subsequent efflux than Ca45 taken up at rest. The results were interpreted as supporting the hypothesis that myometrial contraction is induced by a release of calcium from the inside of the cell membrane and the endoplasmic reticulum, and relaxation follows the removal of ionic cytoplasmic calcium by these same structures.
Article|
July 01 1966
The Influence of High Potassium Depolarization and Acetylcholine on Calcium Exchange in the Rat Uterus
CASEY van BREEMEN,
CASEY van BREEMEN
From the Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada. Dr. van Breemen’s present address is the Department of General Physiology, University of Leicester, Leicester, England
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E. E. DANIEL
E. E. DANIEL
From the Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada. Dr. van Breemen’s present address is the Department of General Physiology, University of Leicester, Leicester, England
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CASEY van BREEMEN
From the Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada. Dr. van Breemen’s present address is the Department of General Physiology, University of Leicester, Leicester, England
E. E. DANIEL
From the Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada. Dr. van Breemen’s present address is the Department of General Physiology, University of Leicester, Leicester, England
Received:
November 01 1965
Online ISSN: 1540-7748
Print ISSN: 0022-1295
© 1966 Chowdhury and Chanda
1966
J Gen Physiol (1966) 49 (6): 1299–1317.
Article history
Received:
November 01 1965
Citation
CASEY van BREEMEN, E. E. DANIEL; The Influence of High Potassium Depolarization and Acetylcholine on Calcium Exchange in the Rat Uterus. J Gen Physiol 1 July 1966; 49 (6): 1299–1317. doi: https://doi.org/10.1085/jgp.0491299
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