Mora S, Dussaubat N, Díaz-Véliz G
Unidad de Farmacología, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Psychoneuroendocrinology. 1996 Oct;21(7):609-20. doi: 10.1016/s0306-4530(96)00015-7.
The influence of the estrous cycle and the effects of exogenous administration of estradiol and progesterone on level of anxiety were studied in intact and ovariectomized rats. Intact Sprague-Dawley female rats were classified according to the stages of estrous cycle. Another group of rats was ovariectomized bilaterally and, 14 days after surgery, they received estradiol benzoate (10 micrograms/kg, s.c.) and/or progesterone (25 mg/kg, s.c.) or corn oil (1 ml/kg). The behavioral tests began 3 h after estradiol or 6 h after progesterone and consisted of: (1) exploration of an elevated plus-maze; and (2) retention of a passive avoidance response. Open-arm exploration of the plus-maze varied according to light intensity and the stages of the estrous cycle. There was a slight increase in open-arm exploration by rats in metestrus, under high light intensity. Low light intensity increased the exploration of the open arms by rats in proestrus and estrus, compared to the other phases of the cycle. Retention of the passive avoidance response was inhibited during proestrus and estrus. Progesterone increased open-arm exploration of the plus-maze under high light conditions, whereas estradiol antagonized this effect. Retention of passive avoidance was inhibited after estradiol or progesterone injection. These results suggest that the behavioral indices of anxiety can vary across the estrous cycle, that low light intensities have anxiolytic-like effects, and that the sensitivity to this effect is higher during proestrus and estrus. This could be explained through modulatory effects of ovarian hormones upon behavioral indices of anxiety.
研究了发情周期以及雌二醇和孕酮的外源给药对完整和去卵巢大鼠焦虑水平的影响。将完整的斯普拉格-道利雌性大鼠根据发情周期阶段进行分类。另一组大鼠进行双侧卵巢切除，术后14天，它们接受苯甲酸雌二醇（10微克/千克，皮下注射）和/或孕酮（25毫克/千克，皮下注射）或玉米油（1毫升/千克）。行为测试在雌二醇给药后3小时或孕酮给药后6小时开始，包括：（1）高架十字迷宫探索；（2）被动回避反应的保持。十字迷宫的开放臂探索根据光照强度和发情周期阶段而变化。在高强度光照下，处于动情后期的大鼠对开放臂的探索略有增加。与发情周期的其他阶段相比,低光照强度增加了处于发情前期和发情期的大鼠对开放臂的探索。在发情前期和发情期，被动回避反应的保持受到抑制。在强光条件下，孕酮增加了对十字迷宫开放臂的探索，而雌二醇则拮抗这种作用。注射雌二醇或孕酮后，被动回避的保持受到抑制。这些结果表明，焦虑的行为指标在发情周期中可能会有所不同，低光照强度具有抗焦虑样作用，并且在发情前期和发情期对这种作用的敏感性更高。这可以通过卵巢激素对焦虑行为指标的调节作用来解释。
