Vanilloid receptor-related osmotically activated channel (VR-OAC), a candidate vertebrate osmoreceptor

The detection of osmotic stimuli is essential for all organisms, yet few os moreceptive proteins are known, none of them in vertebrates. By employing a candidate-gene approach based on genes encoding members of the TRP superfa mily of ion channels, we cloned cDNAs encoding the vanilloid receptor-relat ed osmotically activated channel (VR-OAC) from the rat, mouse, human, and c hicken. This novel cation-selective channel is gated by exposure to hypoton icity within the physiological range. In the central nervous system, the ch annel is expressed in neurons of the circumventricular organs, neurosensory cells responsive to systemic osmotic pressure. The channel also occurs in other neurosensory cells, including inner-ear hair cells, sensory neurons, and Merkel cells.