Millan M J, Millan M H, Reid L D, Herz A
Brain Res. 1986 Aug 27;381(1):29-42. doi: 10.1016/0006-8993(86)90686-4.
Bilateral, radiofrequency lesions of the mediobasal arcuate hypothalamus (MBH) strongly depleted levels of immunoreactive (ir)-beta-endorphin (beta-EP) in the hypothalamus and other brain tissues: these changes reflect destruction of those beta-EP-containing perikarya which are located in the MBH. No change in plasma ir-beta-EP was seen. The ir-dynorphin (DYN) content of the hypothalamus was also depressed while that of ir-Met-enkephalin was unaffected. The fall in hypothalamic ir-beta-EP was correlated with the fall in that of ir-DYN. Lesioned rats displayed only a minor, transient reduction in rate of weight gain between days 3 and 9 postsurgery: this disappeared thereafter. Further, the lesion did not affect the pattern of weight loss and regain associated with 24 h food and water deprivation. Indeed, the total 24 h (daily) food intake (FI) and water intake (WI) of lesioned rats did not differ from that of sham animals while deprivation-induced hyperphagia and hyperdipsia was not attenuated by the lesions. Moreover, the ability of naltrexone to decrease FI and WI (during both dark and light phases of the daily cycle) was not altered by the lesions. These observations indicate that central beta-EP may not be essential for the maintenance of a normal 24 h FI and WI and that opioid antagonists do not act upon the MBH or upon central beta-EP neurones in their suppression of FI and WI. Further, they suggest that central beta-EP may not fulfil an essential role in the control of body weight in the rat. Lesioned rats did, however, reveal a shift in the diurnal rhythmicity of FI and WI reflected in a reduction in the dark:light ratios of these. An alteration in the diurnal rhythmicity of sleeping and core temperature, but not locomotor activity, was also seen. The shifts in hypothalamic ir-beta-EP and ir-DYN (but no other tissue levels of any peptide) were correlated with the magnitude of the shifts in diurnal rhythmicity of ingestive behaviour. Moreover, lesions caudal to the MBH (not affecting hypothalamic ir-beta-EP or ir-DYN) or dexamethasone treatment (which affects pituitary pools of ir-beta-EP and ir-DYN) did not modify these rhythms. Thus, in these respects, the effects are 'particular' to MBH lesions modifying hypothalamic ir-beta-EP and ir-DYN. The data suggest that the MBH may play a role in the modulation of the diurnal scheduling of ingestive behaviour in the rat.(ABSTRACT TRUNCATED AT 400 WORDS)
双侧中基底弓状下丘脑（MBH）的射频损伤显著降低了下丘脑和其他脑组织中免疫反应性（ir）-β-内啡肽（β-EP）的水平：这些变化反映了位于MBH中的含β-EP神经元胞体的破坏。血浆ir-β-EP未见变化。下丘脑的ir-强啡肽（DYN）含量也降低，而ir-甲硫氨酸脑啡肽含量未受影响。下丘脑ir-β-EP的下降与ir-DYN的下降相关。损伤大鼠在术后第3天至第9天之间体重增加率仅出现轻微、短暂的降低：此后这种降低消失。此外，损伤并未影响与24小时食物和水剥夺相关的体重减轻和恢复模式。实际上，损伤大鼠的24小时（每日）总食物摄入量（FI）和水摄入量（WI）与假手术动物并无差异，而剥夺诱导的摄食亢进和饮水亢进并未因损伤而减弱。此外，纳曲酮降低FI和WI的能力（在每日周期的黑暗和光照阶段）并未因损伤而改变。这些观察结果表明，中枢β-EP对于维持正常的24小时FI和WI可能并非必不可少，并且阿片类拮抗剂在抑制FI和WI时并非作用于MBH或中枢β-EP神经元。此外，它们表明中枢β-EP在大鼠体重控制中可能不发挥关键作用。然而，损伤大鼠确实显示出FI和WI的昼夜节律发生了变化，表现为其暗：光比值降低。睡眠和核心体温的昼夜节律也出现了改变，但运动活动未受影响。下丘脑ir-β-EP和ir-DYN的变化（但任何肽的其他组织水平未变）与摄食行为昼夜节律变化的幅度相关。此外，MBH尾侧的损伤（不影响下丘脑ir-β-EP或ir-DYN）或地塞米松治疗（影响垂体池中的ir-β-EP和ir-DYN）并未改变这些节律。因此，在这些方面，这些效应是MBH损伤改变下丘脑ir-β-EP和ir-DYN所特有的。数据表明，MBH可能在调节大鼠摄食行为的昼夜安排中发挥作用。（摘要截取自400字）
