what occurs in olfactory cells once the cation-selective cAMP gated channels open?
current flows inward and the membrane of the olfactory neuron depolarizes. Besides Na, the cAMP gated channel allows substantial amounts of Ca to enter the cilia. In turn the Ca triggers a Ca activated chloride current that may amplify the olfactory receptor potential. (this is a switch from the usual effect of Cl currents, which inhibit neurons; in olfactory cells, the internal Cl concentration must be unusually high so that a Cl current tends to depolarize rather than hyperpolarize the membrane)