[Level of oxytocin release induced by vaginal dilatation (Ferguson reflex) and vagal stimulation (vago-pituitary reflex) in lactating rats (author's transl)].
1. Vaginal dilatation for 30 seconds caused a rapid and brief increase in intramammary pressure which was equivalent to that evoked by 160 muU of oxytocin (Syntocinon) injected intravenously. 2. The rise in mammary pressure induced by the stimulation of the central end of a severed vagus nerve for 30 seconds (5 V, 0,5 ms, 50 HZ) was similar to the response obtained with an intravenous injection of 360 muU of oxytocin. 3. The vago-pituitary reflex leads to the liberation of large amounts of antidiuretic hormone which does not interfere with the effect of oxytocin on the mammary gland, since dexamethasone phosphate prevented the vasopressor effect without significantly affecting the increase in intramammary pressure.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology; D004106:Dilatation; D004558:Electric Stimulation; D005260:Female; D007774:Lactation / Q000187:drug effects; D010121:Oxytocin / Q000378:metabolism* / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D012018:Reflex; D014621:Vagina / Q000294:innervation* / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology*
D010121:Oxytocin; D003907:Dexamethasone
Importance de la libération d'ocytocine induite par la dilatation vaginale (réflexe de Ferguson) et la stimulation vagale (réflexe vago-pituitaire) chez la ratte