BLOCKAGE OF URINARY RESPONSES BY INHIBITORS FOR IP3-MEDIATED PATHWAY IN RAT VOMERONASAL SENSORY NEURONS

The mammalian vomeronasal system is involved in the effects of urinary chemicals on gonadal functions and sexual behaviors. For example, exp osure to urine affects the timing of oestrous cycles in rats. Rat vome ronasal sensory neurons in slice preparation were studied under on-cel l patch clamp conditions. We found that urine excreted from male Wista r rats increased impulse frequency in vomeronasal sensory neurons of f emale Wistar rats. The urinary responses were blocked by an inositol-1 ,4,5-trisphosphate (IP3)-channel inhibitor (10 mu M ruthenium red) or phospholipase C inhibitors (10 mu M U-73122 and 1 mM neomycin), sugges ting that pheromone-like substances in the urine induce the response i n the rat vomeronasal sensory neurons via the IP3-dependent transducti on pathway. (C) 1997 Elsevier Science Ireland Ltd.