Loss of K+Homeostasis in Trout Hepatocytes during Chemical Anoxia: A Screening Study for Potential Causes and Mechanisms

In isolated trout hepatocytes intoxication with CN−(chemical anoxia) leads to a rapid breakdown of K+homeostasis. In the present study an attempt has been made to identify the causes and mechanisms underlying this phenomenon. Our results indicate that neither Ca2+elevation nor cell swelling, both of which occurred during chemical anoxia and could be prevented by exposure to Ca2+chelating agents or to hyperosmotic conditions, respectively, is solely responsible for the breakdown of K+homeostasis. From a number of inhibitors of dissipative K+fluxes tested, only BaCl2, an inhibitor of voltage-gated K+channels, proved to be effective in significantly reducing K+efflux during chemical anoxia. The KCl cotransporter known to be involved in regulatory volume decrease after hypoosmotic shock does not seem to be activated during CN−-induced cell swelling.