Van Erp A M, Kruk M R, Van Oers H J, Hemmers N M
Ethopharmacology Group, Sylvius Laboratory, Leiden, The Netherlands.
Brain Res. 1993 Feb 19;603(2):296-301. doi: 10.1016/0006-8993(93)91251-m.
Injection of ACTH1-24 as well as alpha-MSH in the paraventricular nucleus of the hypothalamus (PVH) induces intense grooming in the rat. While comparing the details of MSH, ACTH and control grooming, we found that the induction of grooming was highly site specific. Even injection of saline in that specific area produced some grooming, possibly due to the release of endogenous substances. To distinguish between effects caused by the peptides and the effects caused by the injection procedure, we compared the behavioural effects of saline and peptide injections in sites with exactly the same location in the PVH, in a post-hoc matched pairs design. Using this design we found that the grooming response induced by saline is of a limited duration. ACTH1-24 and alpha-MSH prolong grooming beyond that period. Interestingly, rats receiving alpha-MSH continued to groom, while rats receiving ACTH1-24 changed to scratching. This confirms earlier findings suggesting that grooming and scratching have a differential organization at the level of the PVH. Whether the peptides also have a role in the initiation of the grooming response, or just prolong a response caused by other local factors requires another experimental approach.
在下丘脑室旁核（PVH）注射促肾上腺皮质激素1-24（ACTH1-24）以及α-促黑素（α-MSH）会诱发大鼠剧烈理毛。在比较促黑素、促肾上腺皮质激素及对照理毛的细节时，我们发现理毛的诱发具有高度的位点特异性。即使在该特定区域注射生理盐水也会引发一些理毛行为，这可能是由于内源性物质的释放所致。为了区分肽类引起的效应和注射操作引起的效应，我们采用事后配对设计，比较了在PVH中位置完全相同的位点注射生理盐水和肽类的行为效应。采用这种设计，我们发现生理盐水诱发的理毛反应持续时间有限。ACTH1-24和α-MSH会使理毛持续时间超过该时间段。有趣的是，接受α-MSH的大鼠会持续理毛，而接受ACTH1-24的大鼠则转变为搔抓。这证实了早期的研究结果，表明在PVH水平，理毛和搔抓具有不同的组织方式。这些肽类是在理毛反应的起始阶段发挥作用，还是仅仅延长由其他局部因素引起的反应，这需要另一种实验方法来研究。
