Inoue M, Maeda M, Takao S, Hayashida Y, Nakai M, Fukushima T, Tomonaga M, Sapru H N, Hayashida Y
Department of Systems Physiology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807, Japan.
Pflugers Arch. 1996 Sep;432(5):941-3. doi: 10.1007/s004240050219.
The present study was undertaken to examine the effects of microinjection of sodium nitroprusside (SNP), which releases nitric oxide (NO) spontaneously, into the nucleus tractus solitarii (NTS) on cerebral circulation. Cerebral blood flow (CBF) was measured in urethane-anesthetized (1.5 g middle dotkg-1, i.p.), paralysed and artificially ventilated rats using labeled microspheres or laser Doppler flowmetry. The CBF was significantly decreased by microinjection of SNP (5 nmol, n=10, microsphere technique; 0.5 nmol, n=6, laser Doppler flowmetry) into the unilateral NTS. Microinjection of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO, prevented cerebral vasoconstrictor responses induced by microinjection of L-glutamate into the NTS (n=10). Microinjection of NG-monomethyl-D-arginine (D-NMMA) had no effect on the cerebral vasoconstrictor responses induced by L-glutamate (n=11). Unilateral microinjections of L-NMMA into the NTS (n=9), of SNP into the area adjacent to the NTS (n=9), of vehicle solution into the NTS (n=10), and of light-inactivated SNP into the NTS (n=6) had no effect on cerebral circulation. Cerebral autoregulation was well maintained in our protocols (n=9). These results indicate that microinjection of SNP, an NO donor, into the NTS decreases CBF.
本研究旨在探讨向孤束核（NTS）微量注射可自发释放一氧化氮（NO）的硝普钠（SNP）对脑循环的影响。采用放射性微球或激光多普勒血流仪，在氨基甲酸乙酯麻醉（1.5 g·kg⁻¹，腹腔注射）、麻痹并人工通气的大鼠中测量脑血流量（CBF）。向单侧NTS微量注射SNP（5 nmol，n = 10，微球技术；0.5 nmol，n = 6，激光多普勒血流仪）可使CBF显著降低。微量注射NO生成抑制剂N⁻甲基⁻L⁻精氨酸（L⁻NMMA）可预防向NTS微量注射L⁻谷氨酸所诱导的脑血管收缩反应（n = 10）。微量注射N⁻甲基⁻D⁻精氨酸（D⁻NMMA）对L⁻谷氨酸所诱导的脑血管收缩反应无影响（n = 11）。向NTS单侧微量注射L⁻NMMA（n = 9）、向NTS相邻区域微量注射SNP（n = 9）、向NTS微量注射赋形剂溶液（n = 10）以及向NTS微量注射光灭活的SNP（n = 6）均对脑循环无影响。在我们的实验方案中脑自动调节功能良好维持（n = 9）。这些结果表明，向NTS微量注射NO供体SNP可降低CBF。
