Changes of cytoplasmic ph in frog nerve-fibers during k+-induced membrane depolarizationстатья
Информация о цитировании статьи получена из
Scopus,
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Frog sciatic nerve and its thin bundles were loaded with fluorescein diacetate in order to monitor changes in cytoplasmic pH (pH(i)) caused by high K+ depolarization. Isosmotic substitution of external Na+ by K+ at pH(o) 7.3 led to a steady concentration-dependent (20-120 mM K+) decrease in pH(i). Elevation of pH, from 7.3 to 8.5 prevented or even reversed these pH(i) changes, indicating their strong dependence on transmembrane H+ fluxes. The depolarization-induced intracellular acidification could not be prevented or decreased by any of the following treatments: removal of external Ca2+; application of the Ca2+ antagonists Ni2+ and Co2+; blockade of K+ channels by TEA; addition to the external solution of Zn2+, a blocker of putative voltage-sensitive H+ channels. By contrast, blockade of Na+ channels by 1-3 mu M TTX prevented the effect of high K+ concentrations on pH(i). It is concluded that the decrease in pH(i) induced by a prolonged membrane depolarization in frog nerve fibers is mainly due to an enhanced H+ influx through non-inactivating Na+ channels.