Heinsbroek R P, van Oyen H G, van de Poll N E
Pharmacol Biochem Behav. 1984 May;20(5):663-8. doi: 10.1016/0091-3057(84)90181-3.
The hypothesis that sex differences in passive avoidance are related to the sex difference in the pituitary-adrenocortical system was studied. A high dose of dexamethasone (500 microg/kg body weight) was injected in male and female rats in order to suppress the activity of the pituitary-adrenocortical system. Dexamethasone treated animals and controls were tested for retention of passive avoidance at one of 4 different intervals after punishment. The percentage of females re-entering the compartment in which they were previously shocked was significantly higher than the percentage of males, after a retention interval of 60 minutes, but not after an interval of 0 minutes or 15 minutes (Experiment 1). Dexamethasone did not affect this pattern of sex differences. The same sex difference was found after an interval of 24 hours (Experiment 2), and again dexamethasone had no effect on it. However, in males a state-dependent effect of dexamethasone treatment was found in Experiment 2 when animals were given two injections of either dexamethasone or saline, one before the learning trial and one before the retention trial. Within the groups of males given two different injections (Dex-Sal and Sal-Dex) a higher percentage re-entered the shock compartment, when compared with the groups of males given the same injection twice (Sal-Sal and Dex-Dex).
(1) A sex difference in passive avoidance apparently occurs after a certain interval during which the animals are not disturbed. (2) This sex difference does not depend on the integrity of the pituitary-adrenocortical system. (3) State-dependency was observed in males only, indicating that changes in the pituitary-adrenocortical system, as a consequence of dexamethasone treatment, may have a more important stimulus value in males.
研究了被动回避中的性别差异与垂体 - 肾上腺皮质系统性别差异相关的假说。给雄性和雌性大鼠注射高剂量地塞米松（500微克/千克体重）以抑制垂体 - 肾上腺皮质系统的活性。在惩罚后的4个不同间隔之一对接受地塞米松治疗的动物和对照组进行被动回避保持测试。在60分钟的保持间隔后，重新进入它们先前受电击隔室的雌性百分比显著高于雄性百分比，但在0分钟或15分钟的间隔后并非如此（实验1）。地塞米松并未影响这种性别差异模式。在24小时的间隔后发现了相同的性别差异（实验2），并且地塞米松再次对其没有影响。然而，在实验2中，当给动物在学习试验前和保持试验前分别注射两次地塞米松或生理盐水时，在雄性中发现了地塞米松治疗的状态依赖性效应。在接受两种不同注射（地塞米松 - 生理盐水和生理盐水 - 地塞米松）的雄性组中，与两次接受相同注射（生理盐水 - 生理盐水和地塞米松 - 地塞米松）的雄性组相比，有更高百分比的动物重新进入电击隔室。
（1）在动物未受干扰的特定间隔后，被动回避中明显出现性别差异。（2）这种性别差异不依赖于垂体 - 肾上腺皮质系统的完整性。（3）仅在雄性中观察到状态依赖性，表明地塞米松治疗导致的垂体 - 肾上腺皮质系统变化在雄性中可能具有更重要的刺激价值。
