PILOT STUDY--PROLACTIN RELEASING PEPTIDE AND NICOTINE

泌乳素（PRL）的分泌不仅支持生殖功能和泌乳，而且在应激下维持体内平衡功能。因此，PRL的释放不仅受内源性释放因子的调控，还受具有抗应激活性的外源性化学物质的调控。其中最突出的是尼古丁，它通过作用中枢神经系统部位，特别是孤束核（NTS），引起PRL的释放。尼古丁调节PRL释放的机制尚不清楚。近年来，研究人员分离出一种能诱导垂体原代细胞释放催乳素的3 - i氨基酸肽，命名为PrRP。我们的初步数据表明，PrRP mRNA存在于NTS中，而其受体存在于下丘脑。这些数据表明PrRP可能是尼古丁诱导PRL释放的另一个重要介质。在尼古丁刺激下，PrRP可能会从NTS释放，作用于下丘脑并诱导其他催乳素释放肽的释放，或者通过在门静脉血液中分泌并直接作用于垂体。因此，我们建议通过证明PrRP存在于尼古丁敏感（~阳性）的NTS神经元中，并且尼古丁诱导PrRP在脑脊液中释放，来验证PrRP与尼古丁之间直接联系的假设。

Prolactin (PRL) is secreted not only to support reproductive functions and lactation but also to maintain homeostatic functions under stress. Consequently, PRL release is known to be regulated not only by endogenous releasing factors but also by exogenous chemical substances with anti-stress activities. Prominent among these is nicotine which causes the release of PRL by acting CNS sites, in particular the nucleus tractus solitarius (NTS). The mechanism by which nicotine modulates PRL release is poorly understood. Recently, a 3 I-amino acid peptide, named the Prolactin Releasing Peptide (PrRP), was isolated which potently induced prolactin release from primary pituitary cells. Our preliminary data indicate that the PrRP mRNA is present in the NTS while its receptor is found in the hypothalamus. These data suggest that PrRP may be another important mediator of nicotine-induced PRL release. Upon nicotine stimulation, PrRP may be released from the NTS to act either on the hypothalamus and induce the release of other prolactin-releasing peptides or by being secreted in the potal blood and acting directly on the pituitary. We therefore propose to test the hypothesis of a direct link between PrRP and nicotine, by showing that PrRP is present in the nicotine sensitive (~ positive) NTS neurons and that nicotine induces PrRP release in the cerebrospinal fluid.