[Study of uterine motor responses to vaginal and uterine stimulations in the ewe in estrus].
We recorded in vivo the electromyographic (EMG) activity of the myometrium in 36 conscious ewes, including ovariectomized animals treated with oestrogen and cyclic animals in oestrus. We studied the motor responses of the uterus to distension of the vagina with a speculum and distension of the uterine horn with a balloon. These two types of stimulation provoked an increase in myometrial activity. By comparing the responses before and after hypophysectomy and before and after treatment with an alpha-adrenergic blocking agent, we were able to evaluate the nature of these responses. Vaginal stimulation induced two types of response: 1) a response of long duration, possibly the result of a spinal reflex followed by a reflex release of oxytocin; 2) a response of short duration, probably resulting simply from a spinal reflex whose efferent pathway is composed of sympathetic fibres. Uterine stimulation activated motility in the stimulated horn only. Thus, the observed increase in EMG activity was not a reflex but the response of the uterine muscle to its own distension.
D000818:Animals; D002369:Castration; D004576:Electromyography; D004837:Epinephrine / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D004971:Estrus; D005260:Female; D007016:Hypophysectomy; D009638:Norepinephrine / Q000494:pharmacology; D010121:Oxytocin / Q000494:pharmacology; D010812:Physical Stimulation; D011247:Pregnancy; D012756:Sheep / Q000502:physiology*; D014590:Uterine Contraction; D014599:Uterus / Q000187:drug effects / Q000502:physiology*; D014621:Vagina / Q000502:physiology
D004967:Estrogens; D010121:Oxytocin; D009638:Norepinephrine; D004837:Epinephrine
Etude des réponses motrices de l'utérus aux stimulations vaginales et utérines chez la Brebis en oestrus.