ISSN:
1432-2013
Keywords:
Free cytosolic calcium
;
Calcium-activated chloride current
;
Isolated smooth muscle cells
;
Noradrenaline
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Ca2+-activated Cl− current in freshly isolated smooth muscle cells from rat portal vein was studied using the whole-cell patch-clamp technique. Simultaneously, the free-cytosolic Ca2+ concentration (Cai) was estimated using emission from the dye Indo-1. Pretreatment of the cells with amytal and carbonyl-cyanide-m-chlorophenylhydrazone, which reduced the intracellular adenosine triphosphate concentration, was used to weaken the cellular Ca2+ homeostatic system. Cai of treated cells slowly increased during perfusion with an external Ca2+-containing solution. This rise in Cai gradually activated a Ca2+-dependent Cl− current which allowed the study of the relationship between activation of this current and Cai levels. The threshold Cai for activation of Cl− channels was around 180 nM and full activation occurred at 600 nM. The Cai dependence of the Cl− channels was not changed during application of noradrenaline and did not depend on the membrane potential. The gating of Ca2+-dependent Cl− channels of rat portal vein myocytes seems to be mainly controlled by intracellular Ca2+
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00374818
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