Ciliary cation conductances in olfactory receptor cells of the clawed toad Xenopus laevis.

One transduction pathway in olfactory receptor neurons is a cascade of receptors, a G-protein, adenylate cyclase, cAMP, and a cyclic nucleotide-activated cation conductance. Here, we show that this conductance is also present in olfactory cells of Xenopus laevis. With optical recordings from the cell's dendritic knob, we show that this conductance, when activated by odors, leads to an increase of intracellular calcium. It is further shown that there is a second cation conductance on the cilia of these cells which is modulated by calcium and can be activated by the application of odorants.