Summary. This paper compares noradrenaline content in the different parts of the oviduct in rabbits receiving or not a dose of estradiol-170 24 h before human chorionic gonadotropin (HCG) and killed 60 h post HCG. 3,4-Dihydroxyphenylalanine assays were carried out in the oviduct after aromatic L-amino acid decarboxylase was inhibited by mhydroxybenzylhydrazine (NSD 1015) in the same experimental conditions. Pauerstein et al. (1974) have shown that an intramuscular injection of 250 pg of estradiol-17R in rabbits 24 h before intravenous injection of 100 IU of HCG delays ovum transport at the ampullary-isthmic junction. The extent of this noradrenergic innervation suggested that estradiol could act at least partially through the noradrenergic systems.Our results show that estradiol-17Q increased oviduct weight by water retention without modifying either the tyrosine hydroxylase activity or the noradrenaline content in any part of the oviduct and that, consequently, the estrogen-induced « tube locking » of ova was not mediated through the noradrenergic processes.Introduction.

Summary ― Spontaneous electromyographic (EMG) activity of the oviduct recorded in vivo inuntreated, estrogen-treated, and progesterone-treated castrated rabbits was found to exhibit two main patterns : short spike bursts lasting 1-10 s and long trains of action potentials lasting several minutes, which constituted the major component of EMG activity.After estrogen treatment, both wet weight and noradrenaline (NA) content of the castrated rabbit oviduct were enhanced mainly at the ampullary-isthmic junction; long trains of discharges were significantly shorter (2.0―2.7 min vs 3.6-4.6 min) and appeared at more frequent intervals (9.8―12.2 min vs 14.2―22.6 min). After progesterone treatment, spontaneous EMG activity was not significantly different from that in untreated castrated rabbits (as was the NA content) except at the ampullary―isthmic junction.NA injection elicited a stimulatory response of the oviduct lasting 1―7 min in the three hormonal states. Phentolamine strongly depressed spontaneous EMG activity but the inhibition was more transient in castrated rabbits than in estrogen-treated and progesterone-treated animals. Propranolol had no effect on spontaneous EMG activity. intervalles plus rapprochés (9,8―12,2 min vs 14,2-22,6 min). Après traitement par la progestérone, l'activité EMG spontanée n'apparaît pas différente de celle enregistrée chez l'animal castré non traité, de même que la teneur de l'oviducte en noradrénaline, sauf pour la jonction isthme―ampoule. Une injection de noradrénaline provoque l'apparition d'une salve de potentiel de 1 à 7 min de durée dans les trois conditions hormonales. La phentolamine déprime fortement l'activité EMG spontanée, mais l'inhibition est plus transitoire chez les lapines castrées non traitées que chez les animaux traités par les estrogènes et par la progestérone. Le propranolol est sans effet sur l'activité EMG spontanée. Ces résultats, ainsi que les teneurs élevées en noradrénaline mesurées dans toutes les parties de l'isthme, montrent qu'il est possible que 1 innervation adréner-gique de l'oviducte joue un rôle dans l'organisation de la motricité spontanée de l'oviducte chez la lapine.activité électromyographique ― stéroïdes sexuels -noradrénaline -oviducte -lapine