Regulation of CRF gene expression in the hypothalamus

点击翻译按钮获取中文摘要

Acetylcholine (ACh) is one of the major neurotransmitters in the brain. ACh-containing nerve terminals are present in the vicinity of corticotropin-releasing factor (CRF) neurons in the paraventricular nucleus of the hypothalamus (PVN).To investigate the role of ACh on CRF synthesis and release ACh was injected directly into the PVN of conscious rats, and changes in CRF mRNA levels in the hypothalamus, POMC mRNA levels in the anterior pituitary (AP) as well as plasma ACTH levels were monitored.1. Plasma ACTH increased following ACh (1-100 pmol) injection into the PVN of conscious rats in a dose-dependent manner, reaching the peak at 30 min and returning to the baseline at 120 min.2. POMC mRNA in the AP and CRF mRNA in the hypothalamic tissue increased dose-dependently 120 min after injection of ACh (0.1-10pmol) into the PVN.3. Pretreatment with icv atropine abolished the ACh-induced increase in plasma ACTH whereas pretreatment with icv hexamethonium had no effect.These results suggest that ACh stimulates CRF synthesis and secretion. Thus, cholinergic inputs to the hypothalamus may regulate positively the CRF neurons in the PVN.The cholinergic influence may be mediated by muscarinic receptors.