Response of cytosolic calcium to anoxia and cyanide in cultured glomus cells of newborn rabbit carotid body.

Microscopic fluorometry was used to examine the effects of anoxia and cyanide (CN-) on cytosolic calcium [Ca2+]i of cultured carotid body (CB) glomus cells from newborn rabbits. Applications of high K+ and veratridine (VRT), a sodium channel activator, induced rapid and marked increases in [Ca2+]i. These effects were inhibited by D600 a calcium channel blocker. [Ca2+]i changes induced by VRT were also blocked by tetrodotoxin (TTX). Glomus cells exhibited a slow increase in [Ca2+]i in response to anoxia and CN-, and a slight decrease during hyperoxia. The effects of anoxia and CN- were blocked by D600 but not by TTX. We conclude that these stimuli induce calcium entry into glomus cells via voltage-dependent Ca2+ channels. Voltage-dependent Na+ channels were not involved.