ELECTRICAL RECORDINGS OF MAGNOCELLULAR SUPRAOPTIC AND PARAVENTRICULARNEURONS DISPLAYING BOTH OXYTOCIN-RELATED AND VASOPRESSIN-RELATED ACTIVITY

In suckled rats, some magnocellular neurons displayed both vasopressin -related phasic activity and oxytocin-related milk ejection bursts. Ch aracteristics of basal activity and interspike intervals resembled tho se of vasopressin neurons. Bursts were coincident with those of oxytoc in neurons and were facilitated by centrally injected oxytocin, but ha d lower maximum instantaneous frequency and often no after-inhibition, These data provide evidence of magnocellular neurones of mixed electr ophysiological phenotype and complement reports of peptide coexistence .