Vomeronasal organ and social factors affect urine marking by male mice

Adult CF-1 male mice cohabited for 15 days with three different females (EXPERIENCED) or remained physically isolated (INEXPERIENCED) prior to removal of their vomeronasal organs (VNX) or a SHAM procedure. Subjects were tested one month after surgery for urine marking in response to a stimulus male, a stimulus female, or no stimulus animal on the opposite side of a screened partition. VNX males exhibited a significant reduction in urine marking compared to SHAM males. EXPERIENCED VNX males deposited urine in amounts that were intermediate to SHAMs and INEXPERIENCED VNX males. These results suggest that deficits in urine marking behavior that result from loss of vomeronasal chemoreception may be ameliorated by prior sexual and/or social experience with females.