This latter observation suggests that normally Harderian gland secretions facilitate delivery of the pheromone and perhaps other nonpolar biologically active molecules to the VNO. Pheromone alone did not significantly increase action potential firing. Receive exclusive offers and updates from Oxford Academic. Although behavioral studies have established the critical involvement of the VN system in detection of this pheromone, the transduction mechanism by snakes with girl sex the pheromone activates snake sensory neurons has yet to be elucidated. Finally, we examined whether female pheromone also had an effect on female VNO neurons. The signal was low-pass filtered at 2 kHz and sampled at 5 kHz. Female pheromone did not evoke inward currents snakes with girl sex female of VN organ neurons. For each reaction, the amount of homogenate used was based on protein concentration only. Stimulation with female pheromone produced inward currents in patch-clamped neurons of male snake VNO slices in a snakes with girl sex manner.