Mechanisms of penile erection during REM sleep regulated by the hypothalamo-limbic system.

为了阐明REM睡眠期间阴茎勃起的调节机制，我们电刺激脑干胆碱能神经元（larerodorsal tegemental nucleus， LDT）内和周围的前丘脑/下丘脑区域，并记录了LDT内的神经元活动。正常阴茎自发勃起模式是由阴茎海绵体（CSP）压力缓慢升高和CSP压力急剧升高与球海绵体（BS）肌肉活动同步组成的。在未麻醉、头部受限的大鼠中，电刺激视前内侧区（MPOA）、视前外侧区（LPOA）、室旁核（PVN）或终纹床核（BST）后，可诱发与正常自发勃起相似的阴茎勃起。其中，PVN反应潜伏期较短。氨基甲酸乙酯麻醉大鼠，勃起仅由MPOA和PVN引起。LDT内及周围也能引起勃起。部分区域的勃起模式几乎正常，而其他区域仅观察到CSP压力的缓慢增加或CSP压力和BS肌肉活动的急剧增加。LDT部分胆碱能神经元在CSP急剧升高前表现出阶段性放电，而另一些神经元在勃起开始前几秒表现出强直性兴奋。这些结果表明，视前区外侧和内侧参与阴茎勃起的方式不同。PVN是阴茎勃起时下丘脑的最后输出。LDT包含有选择性地激活阴茎勃起成分和抑制阴茎勃起成分的系统。

To elucidate the mechanisms involved in regulation of penile erection during REM sleep, we electrically stimulated the proptic/hypothalamic areas, in and around the brainstem cholinergic neurons (larerodorsal tegmental nucleus, LDT) and recorded the neuronal activity in the LDT.Spontaneous normal penile erection pattern is composed of slow increase of pressure in corpus spongeneosum of the penis (CSP) and sharp increase in CSP pressure synchronized with burstic bulbospongiosus (BS) muscle activity. In unanesthetized, head-restrained rats, penile erection which was almost similar to the normal spontaneous one was evoked after the electrical stimulation to the medial preoptic area (MPOA), lateral preoptic area (LPOA), paraventricular nucleus (PVN) or bed nucleus of stria terminalis (BST). Among them, latency of the response was shorter in the PVN. In urethane anesthetized rats, erection was evoked only from the MPOA and PVN. Erection was evoked also in and around the LDT. In some areas, the evoked erection pattern was almost normal, while in other areas only the slow increase in CSP pressure or sharp increase of CSP pressure and BS muscle activity was observed. Some of the the cholinergic neurons in the LDT showed phasic firing before the sharp CSP increase, while others showed tonic increase for several seconds before the initiation of erection.These results indicate that lateral part and medial part of the preoptic area are involved in penile erection in different way. PVN is the final out put in the hypothalamus for penile erection. The LDT contains systems which selectively activate the component of penile erection and those which inhibit penile erection.