Hori T, Yamasaki M, Asami T, Koga H, Kiyohara T
Department of Physiology, Saga Medical College, Japan.
Neuropharmacology. 1988 Sep;27(9):895-901. doi: 10.1016/0028-3908(88)90116-5.
Effects of local application of thyrotropin releasing hormone (TRH) and its metabolite, histidyl-proline diketopiperazine [cyclo (His-Pro)], on the activity of thermosensitive and thermally-insensitive neurons of the anterior hypothalamic-preoptic area were investigated in urethane-anesthetized rats. Microelectrophoretic application of TRH changed the activity of 126 of 206 neurons tested. Thyrotropin releasing hormone predominantly decreased the activity of warm-sensitive neurons and increased the activity of cold-sensitive neurons. Since it has been generally assumed that warm-sensitive and cold-sensitive neurons in the anterior hypothalamic-preoptic area mediate heat and cold defence responses, respectively, the present results are consistent with previous findings showing hyperthermia after injection of TRH into the hypothalamus in the rat. Cyclo (His-Pro) affected the activity of 59 of 153 neurons tested. In addition, cyclo (His-Pro) did not preferentially affect warm- or cold-sensitive neurons. These results indicate that the previously-determined hypothermic effect of cyclo (His-Pro) cannot be explained by its effects on thermosensitive neurons in the anterior hypothalamic-preoptic area.
在氨基甲酸乙酯麻醉的大鼠中，研究了局部应用促甲状腺激素释放激素（TRH）及其代谢产物组氨酰-脯氨酸二酮哌嗪[环（His-Pro）]对下丘脑视前区热敏和热不敏感神经元活动的影响。微电泳施加TRH改变了所测试的206个神经元中126个的活动。促甲状腺激素释放激素主要降低热敏神经元的活动并增加冷敏神经元的活动。由于一般认为下丘脑视前区的热敏和冷敏神经元分别介导热防御和冷防御反应，因此目前的结果与先前的研究结果一致，即在大鼠下丘脑注射TRH后出现体温过高。环（His-Pro）影响了所测试的153个神经元中59个的活动。此外，环（His-Pro）对热敏或冷敏神经元没有优先影响。这些结果表明，先前确定的环（His-Pro）的低温效应不能通过其对下丘脑视前区热敏神经元的作用来解释。
