Milk Ejection during Alcohol Anaesthesia in the Rat

Abstract

THE inhibition of oxytocin release by alcohol during labour and milk ejection has received wide acceptance and studies purporting to show this inhibitory function have been conducted on the rabbit¹, woman² and the rat³. In the last and most recent study, the litter weight gain was measured after a timed exposure to the alcohol-treated doe. Such criteria have, however, been outdated by recent developments. Milk ejection in the rat, and thus oxytocin release, is not the simple reflex process observed in other mammals^4–9. In particular, milk ejection does not occur with the onset of nursing and, even when it does commence, it is an intermittent and an all-or-none event. Furthermore, no anaesthetic has so far been found which blocks this neuroendocrine reflex in the rat. In the light of these developments, therefore, I re-examined the alleged “ethanol block to oxytocin release” and found that the rat, completely anaesthetized with ethyl alcohol, displayed an almost normal pattern of milk ejection.