Excitation of Oxytocin Cells in the Hypothalamic Supraoptic Nucleus by Electrical Stimulation of the Dorsal Penile Nerve and Tactile Stimulation of the Penis in the Rat

In urethane-anaesthetized male rats, electrical stimulation of the dorsal penile nerve (DPN) excited 29 of 48 (60%) oxytocin cells in the contralateral supraoptic nucleus, whereas only 5 of 28 (18%) vasopressin cells were excited by the stimulation. The stimulus applied to the ipsilateral DPN to the recorded neurone also excited a similar proportion of oxytocin cells (25 of 43; 58%). Tactile stimulation of the glans penis excited 7 of 12 (58%) oxytocin cells, whereas the same stimulation excited only 3 of 16 (19%) vasopressin cells. The results suggest that sensory information arising from the penis preferentially excites oxytocin cells in the supraoptic nucleus.