Laboratory of Neuroendocrine Physiology and Metabolism, Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil.
Department of Chemistry, Laboratory of Prebiotic Chemistry, State University of Londrina, Londrina, PR, Brazil.
Endocrine. 2019 Sep;65(3):675-682. doi: 10.1007/s12020-019-02012-w. Epub 2019 Jul 19.
The aim of this study is to evaluate the effects of adrenalectomy (ADX) and glucocorticoid in the changes induced by intracerebroventricular (ICV) administration of vasoactive intestinal peptide (VIP) on food intake and plasma parameters, as well as VIP receptor subtype 2 (VPAC2) mRNA expression in different hypothalamic nuclei of male rats.
Male Wistar rats (260-280 g) were subjected to ADX or sham surgery, 7 days before the experiments. Half of ADX animals received corticosterone (ADX + CORT) in the drinking water. Animals with 16 h of fasting received ICV microinjection of VIP or saline (0.9% NaCl). After 15 min: (1) animals were fed, and the amount of food ingested was quantified for 120 min; or (2) animals were euthanized and blood was collected for biochemical measurements. Determination of VPAC2 mRNA levels in LHA, ARC, and PVN was performed from animals with microinjection of saline.
VIP treatment promoted the anorexigenic effect, which was not observed in ADX animals. Microinjection of VIP also induced an increase in blood plasma glucose and corticosterone levels, and a reduction in free fatty acid plasma levels, but adrenalectomy abolished these effects. In addition, adrenalectomy reduced mRNA expression of VPAC2 in the lateral hypothalamic area and arcuate nucleus, but not in the paraventricular nucleus.
These results suggest that adrenal glands are required for VIP-induced changes in food intake and plasma parameters, and these responses are associated with reduction in the expression of VPAC2 in the hypothalamus after adrenalectomy.
本研究旨在评估肾上腺切除术（ADX）和糖皮质激素对脑室（ICV）给予血管活性肠肽（VIP）引起的食物摄入和血浆参数变化的影响，以及 VIP 受体亚型 2（VPAC2）在雄性大鼠不同下丘脑核中的 mRNA 表达。
雄性 Wistar 大鼠（260-280g）在实验前 7 天进行 ADX 或假手术。一半的 ADX 动物在饮用水中接受皮质酮（ADX+CORT）。禁食 16 小时的动物接受 VIP 或生理盐水（0.9%NaCl）的 ICV 微注射。15 分钟后：（1）动物进食，定量 120 分钟；或（2）动物安乐死，采集血液进行生化测量。对接受生理盐水微注射的动物进行 LHA、ARC 和 PVN 中 VPAC2 mRNA 水平的测定。
VIP 处理促进了厌食作用，但在 ADX 动物中未观察到。VIP 微注射还诱导了血糖和皮质酮水平的升高，以及游离脂肪酸血浆水平的降低，但肾上腺切除术消除了这些作用。此外，肾上腺切除术降低了外侧下丘脑和弓状核中 VPAC2 的 mRNA 表达，但在下丘脑室旁核中没有。
这些结果表明，肾上腺对于 VIP 诱导的食物摄入和血浆参数变化是必需的，这些反应与肾上腺切除后下丘脑 VPAC2 表达减少有关。
