OXYTOCIN DOES NOT ACT LOCALLY IN THE HYPOTHALAMUS TO ELICIT NOREPINEPHRINE RELEASE

An in vitro brain slice preparation was used to determine whether faci litatory effects of systemically administered oxytocin on hypothalamic norepinephrine release result from direct action of the neuropeptide on noradrenergic terminals. When oxytocin was superfused onto hypothal amic slices from ovariectomized control and ovariectomized, hormone-tr eated female rats, the neuropeptide failed to influence either basal o r electrically evoked release of H-3-norepinephrine. Thus, it is likel y that oxytocin facilitates hypothalamic norepinephrine release by a p eripheral mechanism, perhaps vaginocervical contraction.