VOMERONASAL SYSTEM, LHRH, AND SEX BEHAVIOR

Vomeronasal chemosensory input is important for male hamster mating be havior, especially in inexperienced animals. Experiments reviewed here showed that intracerebroventricular injection of luteinizing hormone- releasing hormone (LHRH) substantially restores mating behavior impair ed by removal of vomeronasal organs in inexperienced hamsters. An anal ogue molecule Ac5-10LHRH, which fails to release luteinizing hormone ( LH) from the pituitary, has similar behavioural effects. These finding s are consistent with the idea that vomeronasal sensory input may trig ger intracerebral release of LHRH which then facilitates mating behavi our. Immunocytochemistry for the immediate-early gene-product Fos, use d as an indicator of regional brain activation, indicates a selective activation of central vomeronasal pathways during mating behaviour. Ch emosensory and other sensory inputs contribute to activation in medial amygdala and bed-nucleus of stria terminalis, but medial preoptic/ant erior hypothalamic area activation appears more closely tied to mating behavior itself. Any of these areas may be sites of interaction betwe en vomeronasal chemosensory input and LHRH-containing cells and fibers .