Electrical coupling between cultured glomus cells of the rat carotid body: observations with current and voltage clamping

Electrically coupled pairs of cultured rat glomus cells were used. In one group of experiments, both cells were current-clamped. Delivery of positive or negative pulses to Cell 1 elicited appreciable voltage noise in this cell and large action potentials (probably Ca²⁺ spikes) in about 10% of them. Both passive and active electrical events spread to Cell 2, presumably through the gap junctions between them. The coupling coefficient (K_c) was larger for the spikes than for non-regenerative voltage noise. In another group of experiments, Cell 1 was current-clamped and Cell 2 was voltage-clamped at Cell 1 E_M. Pulses of either polarity, delivered to Cell 1, produced current flow through the intercellular junction and allowed direct measurement of junctional currents (I_j) and total conductances (G_j). I_j had a mean value of about 12.5 pA and G_j of 391 pS. Unitary (presumably single channel) conductance (g_j) was about 78 pS.