Tanaka J, Ushigome A, Matsuda M, Saito H
Department of Human Development, Naruto University of Education, Tokushima, Japan.
Neurosci Lett. 1995 May 19;191(1-2):47-50. doi: 10.1016/0304-3940(95)11555-4.
Twenty-one median preoptic nucleus (MnPO) neurons in normotensive Wistar-Kyoto rats (WKY) and 18 MnPO neurons in spontaneously hypertensive rats (SHR) were antidromically activated by electrical stimulation of the hypothalamic paraventricular nucleus (PVN) under urethane anesthesia. No significant differences in the latency, conduction velocity, or threshold of antidromic activation were observed between WKY and SHR. The spontaneous discharge rate was significantly higher in SHR than in WKY. The activity of these identified MnPO units was examined for response to intracarotid injections of isotonic (0.15 M NaCl solution, 0.05 ml) or hypertonic (0.3 M NaCl solution, 0.05 ml) saline. All the units did not change their activity to the injections of isotonic saline. Of these units, 14 units in WKY and 12 units in SHR displayed and 3 units in WKY and 4 units in SHR exhibited a reduction in neuronal activity following the injections of hypertonic saline, while the remaining 4 units in WKY and 2 units in SHR were unresponsive. The duration and frequency of excitatory response, but not the inhibitory response, caused by the osmotic stimulation was much greater in SHR than in WKY. These results show that MnPO neurons projecting to the PVN may carry the information from osmosensitive elements and that there is a difference between WKY and SHR in the responsivity of these MnPO neurons to the osmotic stimulation.
在乌拉坦麻醉下，通过电刺激下丘脑室旁核（PVN）对21只正常血压的Wistar-Kyoto大鼠（WKY）的视前正中核（MnPO）神经元和18只自发性高血压大鼠（SHR）的MnPO神经元进行逆向激活。WKY和SHR之间在逆向激活的潜伏期、传导速度或阈值方面未观察到显著差异。SHR的自发放电率显著高于WKY。检查这些已鉴定的MnPO单位的活动，以观察其对颈内注射等渗（0.15 M NaCl溶液，0.05 ml）或高渗（0.3 M NaCl溶液，0.05 ml）盐水的反应。所有单位对注射等渗盐水后其活动均未改变。在这些单位中，WKY的14个单位和SHR的12个单位在注射高渗盐水后神经元活动出现降低，而WKY的其余4个单位和SHR的2个单位无反应。SHR中由渗透刺激引起的兴奋性反应的持续时间和频率，而非抑制性反应，比WKY中的大得多。这些结果表明，投射到PVN的MnPO神经元可能携带来自渗透压敏感元件的信息，并且WKY和SHR在这些MnPO神经元对渗透刺激的反应性方面存在差异。
