Hori T, Shibata M, Kiyohara T, Nakashima T, Asami A
Department of Physiology, Saga Medical College, Japan.
Neuropharmacology. 1988 Feb;27(2):135-42. doi: 10.1016/0028-3908(88)90162-1.
The effects of local application of capsaicin on the activity of single thermosensitive neurons in the anterior hypothalamic-preoptic area were studied in the urethane-anesthetized rat. Local injection of capsaicin through a cannula to the vicinity of the neurons increased the activity in 15 of 28 warm-units, decreased the activity in 2 of 4 cold-units and had no effect on 5 of 10 thermally-insensitive units. Electrophoretic application of capsaicin with the use of multibarrelled microelectrodes excited 16 of 27 warm-units, inhibited 12 of 17 cold-units and had no effect on 35 of 60 thermally-insensitive units. Progressive decreases in the responsiveness of the neurons to both capsaicin and the hypothalamic temperature were observed with repeated applications of capsaicin. Many neurons ceased firing after showing excitatory or inhibitory responses to single or repeated applications of capsaicin either by local injection or electrophoretic application. The results may explain the acute thermolytic response, as well as the subsequent decrease in responsiveness to the injection of capsaicin into the anterior hypothalamic-preoptic area, on the basis of changes in the activity of thermosensitive neurons in the anterior hypothalamic-preoptic area.
在氨基甲酸乙酯麻醉的大鼠中，研究了辣椒素局部应用于下丘脑前区-视前区单个热敏神经元活动的影响。通过套管将辣椒素局部注射到神经元附近，28个热敏感单位中有15个活动增加，4个冷敏感单位中有2个活动减少，10个温度不敏感单位中有5个无影响。使用多管微电极电泳施加辣椒素，27个热敏感单位中有16个被兴奋，17个冷敏感单位中有12个被抑制，60个温度不敏感单位中有35个无影响。随着辣椒素的重复应用，观察到神经元对辣椒素和下丘脑温度的反应性逐渐降低。许多神经元在对单次或重复局部注射或电泳应用辣椒素表现出兴奋或抑制反应后停止放电。这些结果可能基于下丘脑前区-视前区热敏神经元活动的变化，解释急性热解反应以及随后对下丘脑前区-视前区注射辣椒素反应性的降低。
