[Ca 2+ outflow from sarcoplasmic reticulum vesicles during changes in membrane potential, Ca2+ concentration and pH].

V A Tugaĭ; G P Diadiusha; A N Zakharchenko

PubMed · 2336728

[Ca 2+ outflow from sarcoplasmic reticulum vesicles during changes in membrane potential, Ca2+ concentration and pH].

V A Tugaĭ·G P Diadiusha·A N Zakharchenko

Abstract

The concentration gradient Ca2+ outflux from the vesicles of the fragmented sarcoplasmic reticulum of rabbit skeletal muscles has been studied under conditions of the induced membrane potential, the concentrations of Ca2+ and H+ in the medium washing over the vesicles being different. The Ca2+ outflux from vesicles is shown to be the same with a decrease of the membrane potential from--80 down to -10 mV and gets higher with the zero and subsequent positive values of the latter. A significant intensification of the Ca2+ outflux from vesicles under the effect of external-vesicular Ca2+ has been observed at its concentration of 10(-5) M. Against this background of external-vesicular Ca2+ and zero value of the membrane potential either exogenous AMP or the pH increase from 6.5 up to 7.8 favour a release of more than 70% of passively accumulated Ca2+. The pH effect grows with a decrease in the external-vesicular concentration of Ca2+. A conclusion is drawn on the significance of protons in the regulation of the Ca2+ release from the sarcoplasmic reticulum.

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Adenosine Monophosphate Animals Calcium Culture Media Hydrogen-Ion Concentration In Vitro Techniques Membrane Potentials Muscles Potassium Rabbits Sarcoplasmic Reticulum English Abstract Journal Article

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V A Tugaĭ, G P Diadiusha, A N Zakharchenko. [Ca 2+ outflow from sarcoplasmic reticulum vesicles during changes in membrane potential, Ca2+ concentration and pH].. https://pubmed.ncbi.nlm.nih.gov/2336728/

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