Pharmacological Properties and Functional Role of a TRP-Related Ion Channel in Lobster Olfactory Receptor Neurons

Abstract

Odors activate lobster olfactory receptor neurons (ORNs) through phosphoinositide signaling that appears to target a Na+-gated nonselective cation channel. The Na+-gated channel is a potential member of the growing family of transient receptor potential (TRP) channels. Here, we test the effect of potential antagonists on the channel in cell-free patches from cultured lobster ORNs. We show that the channel is antagonized by H+ and the TRP channel blockers 2-aminoethoxydiphenyl borate, SKF96365 , ruthenium red, Al3+, Gd3+, and La3+. We then use this enhanced antagonist profile together with the agonists Na+ and Ca2+ to implicate the channel in signal amplification in the cells.