Hypoxia affects differently the intracellular pH of clustered and isolated glomus cells of the rat carotid body.

Clustered and isolated glomus cells, cultured from rat carotid bodies, were exposed to hypoxia (pO2 2-30 torr) induced by applications of sodium-dithionite (Na2S2O4). Hypoxia decreased or increased intracellular pH (pHi) of clustered cells about equally, but lowered it in most isolated cells. The levels of intracellular acidification were similar in both groups whereas alkalinization was more pronounced in the clusters. The H+ equilibrium potential (EH) and its changes during hypoxia (delta EH), were determined almost exclusively by pHi. Seventy-five percent of clustered cells became depolarized whereas 80% of isolated cells underwent hyperpolarization. In both groups, changes in the resting potential (delta EM) were directly and significantly correlated with delta EH, thus delta pHi. These observations support the view that clustered and isolated rat glomus cells behave differently. This difference may occur because of the presence (in the clusters) or absence (in isolated cells) of enveloping sustentacular cell processes.