Role of gonadal steroids on the in vivo acetylcholine release in the hippocampus

隔-海马胆碱能神经元在空间学习记忆功能中起重要作用。最近，我们发现了一个显着的性别差异的24小时乙酰胆碱（Ach）释放在海马的配置文件。在实验I中，为了研究性激素在海马24 h ACh释放中的作用，在自由活动条件下，对完整、去性腺（Gdx）、去性腺睾酮（Gdx+T）和去性腺雌二醇-17 β-预处理（Gdx+E）大鼠进行了超过24 h的在体微透析研究。以20分钟的间隔从背侧海马收集透析液，同时监测同一受试者的自发运动活动。虽然在完整的雄性和骑自行车的雌性大鼠中观察到性别特异性ACh释放曲线，但在Gdx大鼠的两种性别中，暗相期间的ACh释放严重衰减。Gdx+T雄性大鼠和Gdx+E雌性大鼠均成功地恢复了暗期ACh的释放 ...更多信息 而Gdx+T雌性大鼠和Gdx+E雄性大鼠均不能恢复上述各曲线。虽然Gdx显著降低了ACh释放与自发活动之间的相关系数，但Gdx+T雄性大鼠和Gdx+E雌性大鼠都成功地恢复了相关系数。在实验II中，为了进一步研究性激素对海马ACh释放的短期影响，分别在Gdx雄性和Gdx雌性大鼠皮下注射睾酮（2 mg）或雌二醇-17 β（40 μg）。在Gdx雄性大鼠注射替吉奥后，ACh释放逐渐增加，但在最初几小时内明显增加，10小时内恢复到正常雄性大鼠的水平。Gdx雌性大鼠注射17β-雌二醇后，ACh释放量在最初数小时内增加，10小时内恢复到骑自行车雌性大鼠的水平。油注射对ACh释放无明显影响。结果表明：（1）雄性大鼠的睾酮和雌性大鼠的雌二醇-17 β对维持海马ACh的正常释放是必不可少的;（2）性激素可能对ACh的释放有短期影响。少

Septo-hippocampal cholinergic neurons play a significant role in the spatial learning and memory function. We recently revealed a marked sex difference in the profile of 24-h acetylcholine (Ach) release in the hippocampus. In experiment I, to examine the role of sex hormones in the 24-h ACh release in the hippocampus, in vivo microdialysis study was performed in intact, gonadectomized (Gdx), gonadectomized testosterone-primed (Gdx+T), and gonadectomized estadiol-17β-primed (Gdx+E) rats, under the freely moving condition for more than 24 hours. The dialysate was collected from the dorsal hippocampus at 20-min intervals, and spontaneous locomotor activity was simultaneously monitored in the same subject. Although the sex-specific ACh release profile was observed in intact male and cycling female rats, the ACh release during the dark phase was severely attenuated in both sexes of Gdx rats. Both Gdx+T male rats and Gdx+E female rats successfully restored the ACh release during the dark pha … More se, while neither Gdx+T female rats nor Gdx+E male rats restored each profile. Although Gdx significantly decreased in the correlation coefficient between the ACh release and the spontaneous locomotor activity, both Gdx+T male rats and Gdx+E female rats successfully restored the correlation coefficient. In experiment II, to further examine the short-term effect of sex hormones on the ACh release in the hippocampus, testosterone (2 mg) or estadiol-17β (40 μg) was subcutaneously injected in Gdx male and Gdx female rats, respectively. Testosterone injection in Gdx male rats gradually, but significantly increased the ACh release within the first few hours, and it restored the ACh release up to the level in intact male rats within 10 hours. Similarly, estradiol-17β injection in Gdx female rats also increased the ACh release within the first few hours, and restored the ACh release up to the level in cycling female rats within 10 hours. Oil injection showed no significant effects on the ACh release. Present results demonstrated that (1) testosterone in male rats as well as estadiol-17β in female rats are essential to maintain the normal profile of ACh release in the hippocampus, (2) sex hormones may have a short-term effect on the ACh release. Less