EFFECTS OF LOCAL COOLING UPON CONDUCTION AND SYNAPTIC TRANSMISSION
EFFECTS OF LOCAL COOLING UPON CONDUCTION AND SYNAPTIC TRANSMISSION
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DOI：
10.1016/0006-8993(72)90771-8
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发表时间：
1972-01-01
期刊：
影响因子：
2.9
通讯作者：
CONDE, H
中科院分区：
文献类型：
--
作者：
BENITA, M;CONDE, H
描述了一种闭路低温装置及其探头。液体（氟利昂12）和设备的调节膨胀允许在10秒内在−20°C和+20 ° C的范围内获得冷却，精确度为1°C，在哺乳动物大脑的深层结构中。冷却表面仅限于探针的尖端，有一个绝缘真空套延伸到该尖端约1 mm。一项关于红核-丘脑齿状冲动中继的研究表明，在10°C或更高温度下，红核嘴侧水平的冷却可逆地阻断了跨突触兴奋。在红核或头侧的其他地方，即，在丘脑底，即使冷却到较低的温度（0°C以上），也不可能阻断沿着齿状丘脑纤维的传导。这支持了同侧头端传出束的起源位于红核的最头端细胞的理论，即，前红核（NRA）这些结果证明了通过适度冷却来阻断跨突触兴奋而不损害沿着与细胞混合的纤维的传导的可能性。在较低的温度（0°C至-10 °C）下，NRA中的行进纤维中发生可逆的传导阻断。在-10 °C以下，由于冷冻凝固，堵塞变得不可逆。数据的有效性和在急性或慢性实验中使用这种技术产生严格的局部冷却进行了讨论。
A closed circuit cryogenic apparatus, and its probes, are described. The regulated expansion of the liquid (freon 12) and the apparatus allow cooling to be obtained within 10 sec within a range of −20°C and +20°C, with a precision of 1°C, in the deep structures of the mammalian brain. The cooling surface is limited to the tip of the probe, there being an insulating vacuum jacket extending to about 1mm from this tip.A study of the rubro-thalamic relay of dentate impulses shows that, at 10°C or above, cooling localised to the rostral levels of the red nucleus reversibly blocks transsynaptic excitation. Elsewhere in the red nucleus or cephalad,i.e., in the subthalamus, even with cooling to lower temperatures (above 0°C) it is impossible to block conduction along dentato-thalamic fibres. This supports the theory that the origin of a rostral, ipsilateral efferent tract is located in the most rostral cells of the red nucleus,i.e., the anterior red nucleus (NRA). These results demonstrate the possibility of blocking transsynaptic excitation by moderate cooling without impairing conduction along the fibres intermingled with the cells. At lower temperatures (0°C to – 10°C) a reversible blockage of conduction in the coursing fibres in the NRA occurs. Below −10°C the blockage becomes irreversible due to cryocoagulation.The validity of the data and use of this technique for producing strictly localised cooling in acute or chronic experiments are discussed.