Regulation of Ca2+ concentration by second messengers in newt olfactory receptor cell

Abstract

The role of IP3 in olfactory transduction is controversial. This issue was addressed by measuring intracellular Ca2+ concentration under voltage clamp in newt olfactory receptor cells. Odorant stimulation and dialysis of cells with cyclic AMP (cAMP) caused an increase in intracellular Ca2+ concentration that originated in the cilia, as expected from previous works. However, dialysis with IP3 caused a slower rise in Ca2+ concentration that originated in the cell body. Our results suggest that IP3 influences transduction by regulating the intracellular Ca2+ concentration, rather than by carrying the transduction current.