ELECTROPHYSIOLOGICAL PROPERTIES OF FROG OLFACTORY SUPPORTING CELLS

Cells, identified as supporting cells by Lucifer Yellow injection, wer e recorded from slices of frog olfactory epithelium using patch-clamp recordings. Cell-attached single-channel recordings indicated that the intracellular potential (IP) was -68 +/- 7 mV (n = 22) with 4 mM K+ i n the bath ([K+](o)). IP was -67 +/- 4 mV (n = 32) in whole-cell condi tions with 100 mM KCI inside the cell, suggesting a low membrane perme ability for Cl-. IP depended on [K+](o) in a manner described by the G oldman-Hodgkin-Katz equation with a permeability ratio rho(K+):rho(Na) of 40. The input resistance was 32 +/- 14 M Omega (n = 15), indicati ng a high membra ne conductance at rest. Odorant stimulations evoked p assive membrane depolarizations, probably reflecting an increase in [K +](o) due to the neuronal activation. Whole-cell recordings with 100 m M CsCl instead of KCI in the pipette, together with the block of gap-j unctions with octanol, indicated the existence of an electrical coupli ng between supporting cells. The electrical coupling between these gli al-like cells could facilitate the clearance of K(+ )ions released by olfactory receptor neurons during odorant stimulation.