Challet E, Le Maho Y, Pévet P, Nobelis P, Malan A
Centre d'Ecologie et Physiologie Energétiques, CNRS, Strasbourg, France.
Behav Brain Res. 1996 May;77(1-2):155-63. doi: 10.1016/0166-4328(95)00224-3.
The time-course of day-night organization of running wheel activity during prolonged fasting was studied in rats, with or without electrolytic lesions in the ventromedial hypothalamus (VMH). For each individual, dates were referenced to the metabolic transition from lipid to protein utilization in late fasting; this was estimated by daily weighing. In fasted sham-operated controls, daytime activity increased progressively over the fast. This fasting-induced rise in diurnal activity was not due to daily handling, since it was observed also in non-handled (fasted) controls. The pattern of the increase in sham-operated rats differed between 2-hour periods (8-10 h to 18-20 h). The distribution of nocturnal activity was also modified during food deprivation: nocturnal activity in late fasting increased in the 20-22 h period and concomitantly decreased in the two 4-6 h and 6-8 h periods. By contrast, VMH lesions markedly limited and delayed the rise in diurnal running activity, irrespective of the 2-hour period. They prevented any significant change in nocturnal activity pattern over the fast. In fasted sham-operated rats, the data may be interpreted as a phase-advance of the nocturnal pattern of locomotor activity, concomitant with the increase of activity during daytime. These changes were suppressed by the VMH lesions. This suggests that the fasting-induced changes in the day-night pattern of locomotor activity are centrally mediated by a neuronal circuit involving the ventromedial hypothalamus.
在禁食期延长期间，研究了大鼠跑轮活动的昼夜组织的时间进程，这些大鼠的腹内侧下丘脑（VMH）有无电解损伤。对于每只大鼠，时间以禁食后期从脂质利用向蛋白质利用的代谢转变为参照；这通过每日称重来估算。在禁食的假手术对照组中，白天的活动在禁食期间逐渐增加。这种禁食诱导的昼夜活动增加并非由于每日的处理，因为在未处理的（禁食）对照组中也观察到了这一现象。假手术大鼠在不同的2小时时间段（8 - 10小时至18 - 20小时）内活动增加的模式有所不同。在食物剥夺期间，夜间活动的分布也发生了改变：禁食后期的夜间活动在20 - 22小时时间段增加，同时在两个4 - 6小时和6 - 8小时时间段减少。相比之下，VMH损伤显著限制并延迟了昼夜跑步活动的增加，且与2小时时间段无关。它们阻止了禁食期间夜间活动模式的任何显著变化。在禁食的假手术大鼠中，数据可解释为夜间运动活动模式的相位提前，同时白天活动增加。这些变化被VMH损伤所抑制。这表明禁食诱导的运动活动昼夜模式变化是由涉及腹内侧下丘脑的神经回路在中枢介导的。
