Caffeine supresses chloride current fluctuations in calcium-overloaded Xenopus laevis oocytes.

Autor:	Poledna, J.
Další autoři:	Packová, V.
Jazyk:	angličtina
Předmět:	fyziologie člověka kofein human physiology caffeine články journal articles xenopus laevis oocytes chloride currents calcium injection power spectra density
Druh dokumentu:	Non-fiction
ISSN:	0862-8408
Abstrakt:	Abstract: Calcium-induced chloride currents were studied in Xenopus oocytes using the two-electrode voltage clamp technique. Fluctuations of chloride currents measured under a voltage clamp were elicited by injection of calcium into the cytoplasm. Contrary to infrequent injections of small amounts of calcium which evoked smooth transient responses, these fluctuating chloride currents are due to overloading of intracellular calcium stores which then release calcium repeatedly. Chloride current fluctuations in calcium-overloaded oocytes can be reversibly suppressed by caffeine. This effect is concentration dependent and an amplitude decrease of fluctuations is already apparent at 2 mmol/l caffeine. The analysis of power spectra density of fluctuations have displayed the pronounced effect of caffeine. These results suggest that at least a part of the endoplasmic reticulum in Xenopus oocytes is a calcium-releasable calcium store which can be activated at the resting inositol trisphosphate concentration.
Databáze:	Katalog Knihovny AV ČR
Externí odkaz:	Plný text