Intracellular recordings from salamander olfactory supporting cells.

Stable intracellular potentials were recorded just below the surface of the salamander olfactory epithelium. The site of recording corresponded to the zone of highest density of supporting cell perikarya. The electrophysiological properties of cells recorded in this zone included: neither spontaneous nor evoked spike activity, high resting potential (-96 +/- 10 mV, n = 113) and low input resistance (15 +/- 12 M omega, n = 64). The cells were depolarized to -9 +/- 8 mV when the extracellular potassium concentration was increased from 2 to 100 mM. The membrane potential also changed during activation of the olfactory receptor neurons. Antidromic stimulation of olfactory axons elicited both rapid and slow depolarizations. Odorant stimulation induced graded depolarizations which always lagged behind the electro-olfactogram by more than 1 s. In contrast to the responses of the olfactory receptor neurons, these responses were nearly identical from one cell to another. Compared with the concomitant electro-olfactogram, they had almost the same amplitude, with a reversed polarity. These findings are discussed in the context of the possible auxiliary functions of supporting cells in olfactory processes.