长时程冷暴露后大鼠下丘脑脑片视前区温敏神经元的适应性变化

ADAPTIVE CHANGES OF PREOPTIC THERMOSENSITIVE NEURONS IN HYPOTHALAMIC TISSUE SLICES OF RATS AFTER LONG-TERM EXPOSURE TO COLD ENVIRONMENTAL TEMPERATURE

本文比较了生活在冷室（５±１℃，２０只）和暖室（２０±３℃，３５只）达三周的雄性Ｗｉｓｔａｒ大鼠下丘脑脑片视前区神经元电活动和温度敏感性，共记录到１２７个来自暖室组及８６个来自冷室组自发放电神经元。结果表明：（１）冷适应后冷敏神经元的比例明显提高，温度敏感性不变而放电活动的临界温度和下限温度明显下移；（２）热敏神经元的温度敏感性和临界温度降低，但在３７℃时的自发放电活动频率显著增加；（３）非温敏神经元的电活动也增加，其下限温度下移极显著，显示了大鼠视前区神经元在冷适应中的可塑性及其与冷适应中体温调节的机制相关。

In the present work, thermosensitivity and spontaneous firing rate of 86 preopticneurons in hypothalamic tissue slices from 20 cold acclimated rats (CR, at 5± 1 ℃ formore than 3 weeks) and 127 neurons from 35 warm acclimated rats (WR, at 20± 3℃for the same period) were recorded and compared. The results showed that: (1) Thepercentage of cold￣sensitive neurons in CR were higher than that in WR, the criticaltemperature and the lowest temperature of the spontaneous firing activity of cold-sensetive neurons in CR were also lower than that in WR. (2) Thermosensitivity and criticaltemperature of the warm-sensitive neurons in CR were remarkably decreased, and spontaneous firing rate under 37':C was increased. (3) Spontaneous firing rate (37℃ ) oftemperature insensitive neurons in CR were conspicuously increased and the lowest ternperature extended downward. These profound changes in response to long--term cold exposure suggested that plasticity of preoptic neurons was involved in the thermoregulanon in cold adaptation.