Neuropeptide Y treatment and food deprivation increase cyclic AMP response element-binding in rat hypothalamus
Neuropeptide Y treatment and food deprivation increase cyclic AMP response element-binding in rat hypothalamus
复制标题
DOI：
10.1124/mol.51.4.597
复制
发表时间：
1997-04-01
影响因子：
3.6
通讯作者：
Balasubramaniam, A
中科院分区：
文献类型：
--
作者：
Sheriff, S;Chance, WT;Balasubramaniam, A
下丘脑（IHT）注射神经肽Y（NPY）可诱导大鼠产生强烈的摄食反应。我们以前已经表明，NPY诱导的进食是由大鼠百日咳毒素敏感的G蛋白介导的。NPY受体与cAMP和Ca 2+偶联。因为这些第二信使是已知的激活cAMP反应元件结合蛋白，（CREB），cAMP反应元件调节剂，或激活转录因子1，我们研究了这些转录因子在NPY诱导的大鼠进食的参与。与对照注射的脑脊液（1 μ l）相比，IHT管理的NPY增加cAMP反应元件（CRE）结合大鼠下丘脑核提取物的时间依赖性的方式，检测到的电泳迁移率变动分析。相反，IHT给药的厌食神经肽，垂体腺苷酸环化酶激活多肽，强烈抑制CRE结合。食物剥夺48小时也增加CRE结合，而8小时的再喂养正常化CRE活性。用CREB特异性抗体预孵育NPY处理和未进食大鼠的下丘脑核提取物可阻断CRE结合，而用磷酸化CREB抗体预孵育可延缓CRE-蛋白复合物的迁移，表明磷酸化CREB参与了这一过程。一致的，免疫组织化学研究与食物剥夺大鼠室旁核和腹内侧下丘脑中的磷酸化CREB信号显示，在比较大鼠随意喂养。下丘脑钙/钙调素依赖性蛋白激酶II活性也增加IHT-NPY。这些结果表明，钙/钙调素依赖性蛋白激酶II诱导的CREB磷酸化可能参与调节NPY诱导的摄食行为。
Intrahypothalamic (IHT) administration of neuropeptide Y (NPY) induces a robust feeding response in rats. We have shown previously that NPY-induced feeding is mediated by a pertussis-toxin-sensitive G protein in rats. NPY receptors are coupled to cAMP and Ca2+. Because these second messengers are known to activate cAMP response element binding proteins, (CREB), cAMP response element modulators, or activating transcription factor 1, we investigated the involvement of these transcription factors in NPY-induced feeding in rats. Compared with control injections of cerebrospinal fluid (1 mu l), IHT administration of NPY increased cAMP response element (CRE) binding to rat hypothalamic nuclear extracts in a time-dependent manner, as detected by an electrophoretic mobility shift assay. In contrast, IHT administration of the anorectic neuropeptide, pituitary adenylate cyclase activating polypeptide, strongly inhibited the CRE binding. Food deprivation for 48 hr also increased CRE binding, whereas 8 hr of refeeding normalized CRE activity. Preincubation of the hypothalamic nuclear extracts of NPY-treated and unfed rats with antibody specific to CREB blocked CRE binding, whereas preincubation with phosphoCREB antibody retarded the migration of CRE-protein complex, indicating that phosphoCREB is involved in this process. Consistently, immunohistochemical studies with food-deprived rats showed an intense phosphoCREB signal in the paraventricular nuclei and ventromedial hypothalamus in comparison to rats fed ad libitum. Hypothalamic calcium/calmodulin-dependent protein kinase II activity was also increased by IHT-NPY. These results suggest that calcium/calmodulin-dependent protein kinase II induced phosphorylation of CREB may be involved in regulating feeding behavior induced by NPY.