Olfactory responses of chum salmon to amino acids are independent of large differences in salt concentrations between fresh and sea water.

In chum salmon captured at the coastal sea and the natal river, the magnitudes of the olfactory nerve responses to the amino acids after perfusion of the olfactory epithelium with artificial pond water (APW) were similar to those after perfusion with artificial sea water (ASW), although the concentrations of Na+, Cl- and Ca2+ in ASW were 986, 430 and 27 times higher than those in APW, respectively. The findings suggest that the permeability of these ions across the apical membranes of olfactory cells do not essentially contribute to the transduction mechanism in the salmon.