Different effects of hypoxia on the membrane potential and input resistance of isolated and clustered carotid body glomus cells.

Intracellular recordings were made from cultured glomus cells of rat carotid bodies. Hypoxia (PO2 1-61 Torr), induced by Na-dithionite (Na2S2O4), differentially affected cells that were clustered and those that were isolated. More than 80% of clustered cells depolarized and their input resistance decreased, whereas about 60% of isolated cells hyperpolarized and their input resistance increased. In both groups, the mechanisms for cell depolarization or hyperpolarization appeared similar. Differences between clustered and isolated cells seemed to be conditioned by the sustentacular cells. Their processes surrounded clustered cells but were absent around isolated ones. However, we may have also functionally different glomus cells which may or may not correspond to the different types described by anatomists.