The effect of dopamine on glomus cell membranes in the rabbit.

Rabbit carotid bodies were excised and the membrane potentials (MPs) of the glomus cells were recorded in vitro. Upstream injections of dopamine (DA; 25-250 micrograms) elicited a slow, long lasting depolarization in 76% of the cells studied. The remaining 24% were hyperpolarized by DA. Regardless of polarity, the DA-induced potential was associated with a significant increase in input resistance (Ro). On the other hand, changes in MP which were produced artificially by passing direct current through the recording electrode had little effect on Ro. It is concluded that DA alters the MP and Ro of glomus cells and that this may serve to modulate synaptic excitability within the carotid body.