Systemic Leptin Increases the Electrical Activity of Supraoptic Nucleus Oxytocin Neurones in Virgin and Late Pregnant Rats

Sathya Velmurugan, John A Russell, Gareth Leng

Research output: Contribution to journalArticlepeer-review

Abstract

In the rat hypothalamus, fasting attenuates the expression of oxytocin and this can be reversed by exogenous leptin administration. Here, we studied the effects of systemically administered leptin on the electrical activity of magnocellular neurones in the supraoptic nucleus of urethane-anaesthetized rats. In virgin female rats, systemic leptin significantly excited identified oxytocin neurones with no detected effects on the patterning of activity as reflected by hazard function analyses. The lowest dose that was consistently effective was 100μg/ i.v., and this dose had no significant effect on vasopressin neurones. In virgin rats fasted overnight, the spontaneous firing rate of oxytocin neurones was significantly lower than in unfasted rats, but leptin had a similar excitatory effect as in unfasted rats. In late pregnant rats (days 19-21 of pregnancy), spontaneous firing rates of oxytocin neurones were higher than in virgins, and the initial response to leptin was similar to that in virgin rats, but the increase in activity was more persistent. In fasted pregnant rats, the mean spontaneous firing rate of oxytocin neurones was again lower than in unfasted rats, but leptin had no significant effect even at the higher dose of 1 mg/rat. Thus fasting reduced the spontaneous firing rates of oxytocin neurones in non-pregnant rats, and this effect could be reversed by the excitatory effects of leptin. Pregnant rats showed some evidence of leptin resistance, but only after an overnight fast.
Original languageEnglish
Pages (from-to)383-390
Number of pages8
JournalJournal of Neuroendocrinology
Volume25
Issue number4
DOIs
Publication statusPublished - Apr 2013

Fingerprint

Dive into the research topics of 'Systemic Leptin Increases the Electrical Activity of Supraoptic Nucleus Oxytocin Neurones in Virgin and Late Pregnant Rats'. Together they form a unique fingerprint.

Cite this