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 so dium-dithionite (Na2S2O4). Hypoxia decreased or increased intracellula r pH (pH(i)) 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 clus ters. The H+ equilibrium potential (E(H)) and its changes during hypox ia (DELTAE(H)), were determined almost exclusively by pH(i). Seventy-f ive percent of clustered cells became depolarized whereas 80% of isola ted cells underwent hyperpolarization. In both groups, changes in the resting potential (DELTAE(m)) were directly and significantly correlat ed with DELTAE(H), thus DELTApH(i). These observations support the vie w that clustered and isolated rat glomus cells behave differently. Thi s difference may occur because of the presence (in the clusters) or ab sence (in isolated cells) of enveloping sustentacular cell processes.