Vomeronasal organ cannulation in male goats: evidence for transport of fluid from oral cavity to vomeronasal organ during flehmen.

A chronic cannulation procedure is described which allows for sampling vomeronasal organ (VNO) contents repeatedly in freely moving conscious subjects. In 5 male goats an indwelling cannula was used to test the hypothesis that flehmen facilitates the transport of fluid from the oral cavity to the VNO. Flehmen was evoked by placing urine mixed with a tracer dye, sodium fluorescein, in the oral cavity. Water labeled with the same concentration of fluorescein dye was used as a control substance to test for transport during non-flehmen. The VNO contents were sampled during flehmen as well as after non-flehmen and the concentration of dye analyzed by means of a spectrofluorophotometer. The concentration of dye found in the VNO was markedly higher after the occurrence of flehmen than non-flehmen.