Prud'homme M J
Reprod Nutr Dev (1980). 1986;26(3):827-39. doi: 10.1051/rnd:19860507.
The alpha-adrenergic activity of the myometrium was studied by recording the electromyographic activity (EMG) of the uterus in 4 conscious cyclic ewes during oestrus and in 8 conscious pregnant ewes during the last 6 days of gestation. In the cyclic ewes, changes in intra-uterine pressure were recorded at the same time as the EMG. Motor responses to perfusions of phenylephrine, a specific alpha-adrenergic agonist, were studied at three uterine sites. In the ewes in oestrus, uterine activity was stimulated at the three sites by perfusions with phenylephrine (0.6, 2.5, 5 or 10 micrograms/kg/min). The whole uterine horn was alpha-adrenergic-responsive. The effect of the drug was dose-dependent in that the uterine response increased with the dose and reached a plateau at 5 micrograms/kg/min. In the late pregnant ewes, the motor responses to the perfusion of phenylephrine at 10 micrograms/kg/min were studied at three uterine sites once a day during the last 6 days of gestation. Plasma levels of progesterone and total oestrogens were measured at the same time. Up to 48 h before parturition, the effect of phenylephrine depended on the uterine site. The drug had no or little effect at the tubal end of the horn. Phenylephrine stimulated uterine activity at the cervical end of the horn in at least 50% of the ewes. Thus, during this part of gestation, the alpha-adrenergic sensitivity of the myometrium was greater at the cervical than at the tubal end of the uterine horn. Forty-eight hours before parturition, phenylephrine stimulated uterine activity at all three uterine sites in all the ewes. Thus, alpha-adrenergic sensitivity developed over the uterine horn beginning 48 h before parturition at the same time that the oestrogen level increased.
通过记录4只处于发情期的清醒周期性母羊子宫的肌电图活动（EMG）以及8只处于妊娠最后6天的清醒妊娠母羊子宫的肌电图活动，研究了子宫肌层的α-肾上腺素能活性。在周期性母羊中，记录子宫内压变化的同时记录EMG。在三个子宫部位研究了对特异性α-肾上腺素能激动剂去氧肾上腺素灌注的运动反应。在发情期的母羊中，通过灌注去氧肾上腺素（0.6、2.5、5或10微克/千克/分钟）在三个部位刺激子宫活动。整个子宫角对α-肾上腺素能有反应。药物的作用呈剂量依赖性，即子宫反应随剂量增加而增加，在5微克/千克/分钟时达到平台期。在妊娠后期的母羊中，在妊娠最后6天每天一次在三个子宫部位研究对10微克/千克/分钟去氧肾上腺素灌注的运动反应。同时测量血浆孕酮和总雌激素水平。在分娩前48小时内，去氧肾上腺素的作用取决于子宫部位。该药物在子宫角的输卵管端没有作用或作用很小。去氧肾上腺素在至少50%的母羊中刺激子宫角宫颈端的子宫活动。因此，在妊娠的这一阶段，子宫肌层在宫颈处的α-肾上腺素能敏感性高于子宫角的输卵管端。在分娩前48小时，去氧肾上腺素在所有母羊的所有三个子宫部位都刺激子宫活动。因此，在分娩前48小时，随着雌激素水平升高，子宫角开始出现α-肾上腺素能敏感性。
