Role of divalent cations in EOG generation

Underwater EOGs in response to 10–4 M isoamyl acetate were recorded in vivo in frogs. The olfactory mucosa was superfused by sodium-free sucrose solutions, and the effect of the addition of millimolar concentrations of sodium, calcium, cobalt, barium or cadmium was studied. All voltage responses were standardized according to the solution resistivities. Barium and calcium efficiently restored the response; sodium and cobalt were less efficient. Cobalt did not alter the restoring effect of calcium. Cadmium induced an irreversible blockage irrespective of the presence of calcium. These results are discussed in terms of possible ionic mechanisms mediating olfactory responses.