Kita Ichiro, Yoshida Yasushi, Nishino Seiji
Sleep and Circadian Neurobiology Laboratory, Center for Narcolepsy, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA 94304-5489, USA.
Neurosci Res. 2006 Apr;54(4):269-75. doi: 10.1016/j.neures.2005.12.005. Epub 2006 Jan 19.
Intracerebroventricular (ICV) or PVN local injections of oxytocin induce yawning and penile erection, for which a positive feedback mechanism for the PVN oxytocinergic activation is suggested, but this had not been directly substantiated in vivo. We have assessed the behavioral effects and activity of oxytocinergic neurons with double-staining for c-Fos and oxytocin in the PVN after ICV administration of oxytocin in adult male rats. ICV oxytocin injections (50 and 200 ng) dose-dependently induced yawning and penile erection and significantly increased the percentage of c-Fos positive oxytocin neurons in the medial, dorsal and lateral parvocellular subdivision of the PVN. However, increases in the magnocellular portion were not significant. We also found that lithium chloride (LiCl, 0.5 and l.0 mEq), a compound known to activate oxytocinergic neurons, also significantly increased the percentage of c-Fos positive oxytocin neurons in all PVN portions. However, LiCl did not induce yawning and penile erection, but counteracted the oxytocin-induced yawning and penile erection. These results suggest that if the activation of oxytocinergic neurons in the PVN is important for mediating oxytocin-induced yawning and penile erection, a selective activation of parvocellular oxytocinergic neurons in the PVN is likely to be involved.
脑室内（ICV）或室旁核（PVN）局部注射催产素可诱发打哈欠和阴茎勃起，为此有人提出PVN催产素能激活存在正反馈机制，但这一点在体内尚未得到直接证实。我们在成年雄性大鼠脑室内注射催产素后，通过对PVN中c-Fos和催产素进行双重染色，评估了催产素能神经元的行为效应和活性。脑室内注射催产素（50和200纳克）呈剂量依赖性地诱发打哈欠和阴茎勃起，并显著增加了PVN内侧、背侧和外侧小细胞亚区中c-Fos阳性催产素神经元的百分比。然而，大细胞部分的增加并不显著。我们还发现，已知能激活催产素能神经元的化合物氯化锂（LiCl，0.5和1.0毫当量）也显著增加了PVN所有部分中c-Fos阳性催产素神经元的百分比。然而，LiCl并未诱发打哈欠和阴茎勃起，反而抵消了催产素诱发的打哈欠和阴茎勃起。这些结果表明，如果PVN中催产素能神经元的激活对于介导催产素诱发的打哈欠和阴茎勃起很重要，那么PVN中小细胞催产素能神经元的选择性激活可能与之有关。
