Dube M G, Horvath T L, Leranth C, Kalra P S, Kalra S P
Department of Physiology, University of Florida College of Medicine, Gainesville 32610.
Physiol Behav. 1994 Oct;56(4):811-3. doi: 10.1016/0031-9384(94)90247-x.
Central injection of galanin elicits feeding in satiated rats. We recently observed galanin-immunoreactive fibers in synaptic connection with a population of beta-endorphin-immunopositive cell bodies and dendrites in the basal hypothalamus. Because beta-endorphin also stimulates food intake, these morphological findings raised the possibility that stimulation of feeding by galanin may, in part, be mediated by beta-endorphin release. First, we observed that ICV injection of galanin (1.5-6.0 nmol) stimulated feeding in a dose-related fashion. Next, the effect on food intake of the opioid receptor antagonist naloxone (20-200 micrograms, ICV) administered immediately preceding galanin (3 nmol, ICV) was evaluated. Galanin-induced feeding was suppressed by naloxone in a dose-dependent manner with a maximal suppression of 76% at the highest naloxone dose. These findings support the existence of a functional link between galanin and beta-endorphin and are in accord with the view that stimulation of food intake by galanin may, in part, be mediated by increased beta-endorphin release.
向饱足的大鼠脑室内注射甘丙肽会引发进食。我们最近观察到在下丘脑基部，有甘丙肽免疫反应性纤维与一群β-内啡肽免疫阳性的细胞体和树突形成突触连接。由于β-内啡肽也能刺激食物摄入，这些形态学发现提示甘丙肽刺激进食的作用可能部分是由β-内啡肽释放介导的。首先，我们观察到脑室内注射甘丙肽（1.5 - 6.0纳摩尔）以剂量相关的方式刺激进食。接下来，评估了在注射甘丙肽（3纳摩尔，脑室内注射）之前立即注射阿片受体拮抗剂纳洛酮（20 - 200微克，脑室内注射）对食物摄入的影响。纳洛酮以剂量依赖的方式抑制甘丙肽诱导的进食，在最高纳洛酮剂量时最大抑制率达76%。这些发现支持了甘丙肽与β-内啡肽之间存在功能联系的观点，并且与甘丙肽刺激食物摄入可能部分由β-内啡肽释放增加介导的观点一致。
