Haak L L, Mignot E, Kilduff T S, Dement W C, Heller H C
Department of Psychiatry, Stanford University, CA 94305.
Brain Res. 1991 Nov 1;563(1-2):215-20. doi: 10.1016/0006-8993(91)91536-a.
We assayed various brain regions for levels of monoamines and their metabolites throughout the hibernation cycle of the golden-mantled ground squirrel Spermophilus lateralis. The tissue concentrations of serotonin, dopamine, norepinephrine and their metabolites were determined in the parietal cortex, striatum, midbrain, hippocampus, hypothalamus, and pons. Telencephalic regions exhibited the most significant variations in biogenic amine content. Cortical serotonin (5-HT) levels increased significantly at entrance (P less than 0.0001) relative to other periods of the hibernation cycle, suggesting a role for 5-HT in the initiation of hibernation. Among striatal dopamine (DA) metabolites, 3-methoxytyramine was detectable only during euthermia and arousal; from entrance through arousal, homovanillic acid (HVA) levels were half that found during euthermia (P = 0.0001); and dihydroxyphenylacetic acid (DOPAC) levels increased during day 1 of hibernation (P less than 0.0005). Midbrain DA (P = 0.0295) and hippocampal HVA (P = 0.0194) levels also changed significantly across the hibernation bout. The absence of a consistent change in any monoamine or metabolite throughout the brain precludes the possibility of preferential temperature-dependent impairment of an enzyme involved in biogenic amine synthesis or degradation and suggests that the levels observed reflect changes in neural activity specific to each brain region. Together with previous studies of brain 2-deoxyglucose uptake throughout the hibernation cycle, these data indicate that a transient change in afferent monoaminergic metabolism and neurotransmission in the forebrain is a necessary component for the entrance to hibernation.
我们在侧纹黄鼠（Spermophilus lateralis）整个冬眠周期中，检测了其各个脑区中单胺及其代谢物的水平。测定了顶叶皮质、纹状体、中脑、海马体、下丘脑和脑桥中血清素、多巴胺、去甲肾上腺素及其代谢物的组织浓度。端脑区域的生物胺含量变化最为显著。相对于冬眠周期的其他阶段，皮质血清素（5-羟色胺，5-HT）水平在进入冬眠时显著升高（P<0.0001），这表明5-HT在冬眠起始过程中发挥作用。在纹状体多巴胺（DA）代谢物中，3-甲氧基酪胺仅在正常体温和觉醒期间可检测到；从进入冬眠到觉醒，高香草酸（HVA）水平仅为正常体温期间的一半（P = 0.0001）；二羟基苯乙酸（DOPAC）水平在冬眠第1天升高（P<0.0005）。中脑DA水平（P = 0.0295）和海马体HVA水平（P = 0.0194）在整个冬眠期间也有显著变化。整个大脑中任何单胺或代谢物均未出现一致变化，这排除了生物胺合成或降解相关酶优先受到温度依赖性损伤的可能性，表明所观察到的水平反映了每个脑区特定的神经活动变化。结合先前关于整个冬眠周期脑内2-脱氧葡萄糖摄取的研究，这些数据表明，前脑传入单胺能代谢和神经传递的短暂变化是进入冬眠的必要组成部分。
