Odorant-induced Hyperopolarization and Suppresion of cAMP-activated Current inNewt Olfactory Receptor Neurons

摘要

Although many studies have reported that odorants can elicit inhibitory responses as well as excitatory responses in vertebrate olfactory receptor neurons, the cellular mechanisms that underlie this inhibition are unclear. Here we examine the inhibitory effect of odorants on nevvt olfactory receptor neurons using whole cell patch clamp recording. At high concentrations, odorant stimulation decreased the membrane conductance and inhibited depolarization. Various odorants {anisole, isoamyl acetate, cineole, limonene and isovaleric acid) suppressed the depolarizing current in a dose-dependent manner. Furthermore, one odorant could suppress the depolarization caused by another odorant. The depolarizat)on caused by isoamyl acetate was f inhibited by anisole in cells that were excited by isoamyl acetate but not by anisole. Odorants were able to hyperpolarize cells :. that were depolarized by cAMP-induced conductance. Given that this inhibitory effect of odorants can affect excitation caused by other odorants, we suggest that it might playa role in coding odorants in olfactory receptor neurons.