Central action of proteinacious hormones

在蝾螈，Cynops pyrrhogaster，内部受精发生，尽管没有交配器官。为了将精包转移到雌性泄殖腔中，雄性会进行独特的求偶行为。我们前期的研究表明，除了雄激素外，催乳素（PRL）和精氨酸催产素（AVT）也参与求爱行为的表达，并且催乳素（PRL）和精氨酸催产素（AVT）都是诱发求爱行为的中枢神经元。利用抗催乳素受体抗体的免疫组织化学研究表明，脉络丛和含AVT的神经元都具有催乳素受体。此外，使用AVT受体抑制剂的药理学研究表明，AVT在诱发行为方面的作用是通过Vla受体介导的，其在间脑中的分布局限于视前区、视交叉上核和腹侧下丘脑。这提示PRL通过脉络丛进入脑内作用于AVT神经元，AVT介导PRL的作用。为了证明这一假设，使用雄激素引发的雄性蝾螈进行了实验。首先证实了侧脑室注射抗PRL抗体或抗PRL受体抗体可阻断求偶行为的表达，而AVT可恢复求偶行为的表达。另一方面，Vla受体抑制剂的侧脑室给药诱导的行为抑制从未被PRL补充所抵消。这些结果表明，PRL主要作用于AVT神经元，AVT介导了PRL诱导求偶行为的作用。

In the newt, Cynops pyrrhogaster,internal fertilization takes place in spite of the absence of copulatory organs. In order to transfer the spermatophore into the cloaca of the female, the male performs an unique courtship behavior. Our previous study revealed that besides androgen, prolactin(PRL) and arginine vasotocin(AVT) are involved in the expression of the courtship behavior and that both PRL and AVT act centrally to elicit the behavior .Immunohistochemical study using antibody against PRL receptor demonstrated that both the choroidal plexus and AVT containing neurons possess PRL receptors. Moreover pharmacological study using inhibitors of AVT receptors revealed that the action of AVT in terms of eliciting the behavior is mediated through Vla receptor, its distribution in the diencephalon being confined to the preoptic area, suprachiasmatic nucleus and ventral hypothalamus. This raised the possibility that PRL incorporated into the brain through the choroidal plexus acts on the AVT neurons and AVT mediates the action of PRL. To prove this hypothesis, experiments were conducted using androgen-primed male newts. Firstly it was confirmed that intracerebroventricular injection of antibody against PRL or antibody against PRL receptor blocked the expression of courtship behavior and that administration of AVT restored the expression of courtship behavior. On the other hand, the suppression of the behavior induced by the intracerebroventricular administration of an inhibitor of Vla receptor was never nullified by PRL supplementation. These results indicate that PRL primarily acts on the AVT neurons and AVT mediates the action of PRL to elicit the courtship behavior.