Luque E H, Castro-Vazquez A
Endocrinology. 1983 Jul;113(1):385-90. doi: 10.1210/endo-113-1-385.
The sensory mechanisms that participate in the induction of pseudopregnancy after a single injection of progesterone were investigated. Unless otherwise indicated, rats were kept in group cages and vaginal smears were taken daily. Progesterone evoked pseudopregnancy in a dose-dependent manner when administered to proestrous or estrous rats that received no cervicovaginal stimulation. The probability of pseudopregnancy after progesterone was higher on estrus. Cervicovaginal stimulation of proestrous rats that received 5 mg progesterone 10 h before was performed with a rod with a sliding stop attached to regulate its intravaginal penetration. Progesterone facilitated responsiveness to this stimulus, although the amount injected was not significantly effective in increasing the incidence of pseudopregnancy in nonstimulated rats. However, the mere application of the stop of the stimulator on the perineal skin was followed by a significantly higher incidence of pseudopregnancy in progesterone-injected rats than in their vehicle-injected controls, which suggested an action of the steroid on perineal sensitivity. Accordingly, the pseudopregnancy-evoking effect of progesterone was clearly inhibited by refraining from taking vaginal smears for 5 days after steroid injection on estrus. No further inhibition was observed after isolating the animals in single rat cages. However, daily finger stimulation of the perineal skin of nonsmeared rats restored to a normal level response to progesterone. Furthermore, this response was severely impaired by transecting the pudendal nerves before the injection. It is concluded that pseudopregnancy is induced in progesterone-treated rats through sensory stimulation of the pudendal receptive field and it is suggested that the pudendal nerve may subserve as a secondary afferent system to elicit the pseudopregnancy response. The possibility progesterone also acts on other afferent systems including the main afferent system constituted by the pelvic nerve is discussed.
研究了单次注射孕酮后参与诱导假孕的感觉机制。除非另有说明，大鼠饲养在群笼中，每天进行阴道涂片检查。当将孕酮给予未接受宫颈阴道刺激的动情前期或动情期大鼠时，孕酮以剂量依赖性方式诱发假孕。孕酮处理后假孕的概率在发情期更高。对在10小时前接受5mg孕酮的动情前期大鼠进行宫颈阴道刺激，使用带有滑动止动器的棒来调节其阴道内插入深度。孕酮促进了对这种刺激的反应性，尽管注射的量在增加未刺激大鼠的假孕发生率方面没有显著效果。然而，仅仅将刺激器的止动器应用于会阴皮肤后，注射孕酮的大鼠假孕发生率明显高于注射赋形剂的对照大鼠，这表明该类固醇对会阴敏感性有作用。因此，在发情期注射类固醇后5天不进行阴道涂片检查，明显抑制了孕酮诱发假孕的作用。将动物隔离在单笼中后未观察到进一步的抑制作用。然而，每天对未涂片大鼠的会阴皮肤进行手指刺激可使对孕酮的反应恢复到正常水平。此外，在注射前切断阴部神经会严重损害这种反应。得出的结论是，在孕酮处理的大鼠中，通过阴部感受野的感觉刺激诱导假孕，并且提示阴部神经可能作为二级传入系统引发假孕反应。还讨论了孕酮是否也作用于包括由盆神经构成的主要传入系统在内的其他传入系统的可能性。
