Orexin A (hypocretin 1) injected into hypothalamic paraventricular nucleus and spontaneous physical activity in rats
Orexin A (hypocretin 1) injected into hypothalamic paraventricular nucleus and spontaneous physical activity in rats
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DOI：
10.1152/ajpendo.00126.2003
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发表时间：
2004-04-01
影响因子：
5.1
通讯作者：
Levine, JA
中科院分区：
文献类型：
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作者：
Kiwaki, K;Kotz, CM;Levine, JA
在人类中，非运动活动产热（NEAT）随着正能量平衡而增加。正能量平衡与身体活动之间相互作用的中介尚不清楚。在这项研究中，我们提出了一种假说，即食欲素A在下丘脑室旁核（PVN）中起作用，以增加非进食相关的身体活动。pvn插管大鼠分别在明暗周期注射食欲素A或载药。自发体力活动（SPA）测量采用红外活动传感器阵列和夜视录像（VTR）。用间接量热法测定O-2消耗量和CO2产量。用VTR法评价摄食行为。无论注射时间如何，进食素A （1 nmol）与注射后2 h SPA显著增加相关(进食素A: 6.27 +/- 1.95 × 10(3)束断计数，n = 24；载体：1.85±1.13 × 10(3), n = 38)。SPA的增加伴随着O-2消耗的相应增加。摄食素A仅在光照早期注射时才会增加摄食时间，仅占增加体力活动的3.5 +/- 2.5%。在剂量-反应实验中，SPA的增加与食欲素a的剂量呈线性相关，直至2 nmol。PVN注射的食欲素受体拮抗剂SB-334867与SPA的降低和PVN注射的食欲素A的作用减弱有关。因此，食欲素A可以在PVN中起作用，增加非摄食相关的身体活动，表明该神经肽可能是NEAT的中介。
In humans, nonexercise activity thermogenesis (NEAT) increases with positive energy balance. The mediator of the interaction between positive energy balance and physical activity is unknown. In this study, we address the hypothesis that orexin A acts in the hypothalamic paraventricular nucleus (PVN) to increase nonfeeding-associated physical activity. PVN-cannulated rats were injected with either orexin A or vehicle during the light and dark cycle. Spontaneous physical activity (SPA) was measured using arrays of infrared activity sensors and night vision videotaped recording (VTR). O-2 consumption and CO2 production were measured by indirect calorimetry. Feeding behavior was assessed by VTR. Regardless of the time point of injection, orexin A (1 nmol) was associated with dramatic increases in SPA for 2 h after injection ( orexin A: 6.27 +/- 1.95 x 10(3) beam break count, n = 24; vehicle: 1.85 +/- 1.13 x 10(3), n = 38). This increase in SPA was accompanied by compatible increase in O-2 consumption. Duration of feeding was increased only when orexin A was injected in the early light phase and accounted for only 3.5 +/- 2.5% of the increased physical activity. In a dose-response experiment, increases in SPA were correlated with dose of orexin A linearly up to 2 nmol. PVN injections of orexin receptor antagonist SB-334867 were associated with decreases in SPA and attenuated the effects of PVN-injected orexin A. Thus orexin A can act in PVN to increase nonfeeding-associated physical activity, suggesting that this neuropeptide might be a mediator of NEAT.