Changes of characteristics of preoptic neurons and NA metabolism in hypothalamus of ground squirrel (Citelleus Dautieus) in different seasons and hibernating phases  

作　　者：孙久荣 马永超 许兆辉 赵文剑 董金辉 蔡益鹏 

出　　处：《Science China(Life Sciences)》1998年第5期488-497,共10页中国科学（生命科学英文版）

基　　金：ProjectsupportedbytheNationalNaturalScienceFoundationofChina (GrantNos.392 30 0 6 0and 395 70 10 0 ) .

摘　　要：The unit firing activities of neurons in the preoptic area (POA) of ground squirrel hypothalamic tissue slices were recorded and the metabolism of NA in hypothalamus was measured with high performance liquid chromatography (HPLC). Thermosensitivity, proportions, the critical temperature (Tc) and the lowest temperature (TL) of firing activity of the above mentioned neurons, and NA metabolism in hypothalamus were compared in different seasons and hibernating phases. In comparison with that in summer euthermar, it was shown that (i) the percentage and thermosensitivity of the POA neurons varied respectively in the hibernating phases; (ii) TL and Tc of the POA neurons in winter, both euthermar and hibernation, were markedly decreased; (iii) the POA neurons in hibernation became much more sensitive to NA, and the response of cold sensitive neurons to NA changed from inhibiting pattern in summer to exciting one in hibernation; (iv) the contents and metabolism of NA in hypothalamus decreased significantly in the entering phase and deep hibernation phase, while the metabolism of NA increased remarkably in the arousal phase. These changes might explain the regulatory mechanism how ground squirrel actively decreases body temperature (Tb) in entering into hibernation and quickly recovers body temperature in arousal phase.The unit firing activities of neurons in the preoptic area (POA) of ground squirrel hypothalamic tissue slices were recorded and the metabolism of NA in hypothalamus was measured with high performance liquid chromatography (HPLC). Thermosensitivity, proportions, the critical temperature (Tc) and the lowest temperature (TL) of firing activity of the above mentioned neurons, and NA metabolism in hypothalamus were compared in different seasons and hibernating phases. In comparison with that in summer euthermar, it was shown that (i) the percentage and thermosensitivity of the POA neurons varied respectively in the hibernating phases; (ii) TL and Tc of the POA neurons in winter, both euthermar and hibernation, were markedly decreased; (iii) the POA neurons in hibernation became much more sensitive to NA, and the response of cold sensitive neurons to NA changed from inhibiting pattern in summer to exciting one in hibernation; (iv) the contents and metabolism of NA in hypothalamus decreased significantly in the entering phase and deep hibernation phase, while the metabolism of NA increased remarkably in the arousal phase. These changes might explain the regulatory mechanism how ground squirrel actively decreases body temperature (Tb) in entering into hibernation and quickly recovers body temperature in arousal phase.

关 键 词：HIBERNATION HYPOTHALAMUS THERMOSENSITIVE neuron NORADRENALINE cold tolerance. 

分 类 号：Q958.117[生物学—动物学]