Functional conections between right & left hypothalamus in thermcregulation.

本研究通过测量单侧POAH加温电刺激或单侧腹部皮肤热刺激时足部皮肤血管舒缩活性和后肢肌肉冷致寒战，探讨麻醉大鼠中枢神经热调节控制的偏侧性。单侧POAH升温使身体两侧血管舒张，但同侧血管舒张要么发生在较低的下丘脑温度阈值下，要么比对侧血管舒张更强。在低温环境（5ºC）下，当加热POAH一侧时，两条后腿同时抑制颤抖，当加热停止时，两条后腿同时出现颤抖。这些结果表明，不同的热调节效应受到POAH两侧不同方式的调节。在接下来的一系列实验中，通过细胞外记录在局部温度变化和电刺激对侧下丘脑前部（POAH）时，氨基乙酯麻醉大鼠视前区和下丘脑前部（POAH）的单单位活性，测试了左右两侧视前区和下丘脑前部（POAH）之间直接交换温度调节控制信息的可能性。123个神经元中，对侧刺激促进了24个神经元，抑制了20个神经元；没有反转录激活。在82个测试热敏性的神经元中，有27个是热敏性的，20个是冷敏性的：神经元的热敏性与其对侧刺激的反应没有显著相关。对侧刺激反应发生率最高（60%）的发现，当刺激和记录部位都在POAH的前半部分时。在对前联合及其吻侧区进行正中矢状切断术后，这些反应就消失了。这些结果表明在POAH前部的左右两侧之间存在丰富且主要的多突触连接。少

The present study explored the laterality of central nervous thermoregulatory control in anesthetized rats by measuring paw skin vasomotor activity and cold-induced shivering in hind leg muscles during unilateral POAH warming and electrical stimulation or during unilateral thermal stimulation of abdominal skin. Unilateral POAH warming produced vasodilation on both sides of the body, but vasodilation on the ipsilateral side always either occurred at a lower threshold hypothalamic temperature or was stronger than on the contralateral side. In a cold environment(5ﾟC), shivering was suppressed simultaneously in both hind legs when one side of the POAH was warmed, and shivering reappeared simultaneously on both sides when POAH warming stopped. These results suggest that different thermoregtilarory effectors are regulated in a different way by each side of the POAH. In the next series of experiments, the possibility of direct exchange of thermoregulatory control information between the left … More and right sides of the preoptic area and anterior hypothalamus(POAH)was tested by extracellularly recording single unit activity in the POAH of urethane-anaesthetized rats during local temperature changes and electrical stimulation of the contralateral POAH. Twenty-four of 123 neurons were facilitated and 20 inhibited by contralateral stimulation ; none were antidromically activated. Twenty-seven of the 82 of these neurons tested for thermosensitivity were warm-sensitive, and 20 were cold-sensitive : a neuron's thermosensitivity was not significantly correlated with its response to contralateral stimulation. The highest incidence of response to contralateral stimulation(60%)was found when stimulation and recording sites were both in the anterior half of the POAH. These responses were absent after midsagittal transection of the anterior commissure and its rostral area. These results indicate plentiful and predominantly polysynaptic connections between the right and left sides of the anterior POAH. Less