Inoue M, Maeda M, Takao S
Department of Systems Physiology, University of Occupational and Environmental Health, Kitakvushu, Japan.
J Auton Nerv Syst. 1997 Apr 14;63(3):172-8. doi: 10.1016/s0165-1838(97)00006-4.
This study was undertaken to examine the effects of the activation of the neurons in the nucleus tractus solitarius (NTS) via microinjection of sodium nitroprusside (SNP), which spontaneously releases nitric oxide (NO), on the blood flows of the spleen, kidney, liver, brain and spinal cord and to investigate the regional differentiation of the blood flow changes between those organs. Employing urethane-anesthetized (1.5 g kg-1, i.p.), paralyzed and artificially ventilated rats, regional blood flows of those organs were determined simultaneously using radiolabeled microspheres (109Cd, 51Cr and 85Sr) Unilateral microinjection of SNP into the NTS (n = 9) decreased brain blood flow from 71 +/- 8 (mean +/- S.E.) to 54 +/- 6 (P < 0.01) and spinal cord blood flow from 58 +/- 8 to 43 +/- 5 ml min-1 (100 g)-1 (P < 0.05) and increased brain vascular resistance from 1.18 +/- 0.13 to 1.48 +/- 0.15 (P < 0.01) and spinal cord vascular resistance from 1.46 +/- 0.17 to 1.80 +/- 0.16 (P < 0.05) mmHg per [ml min-1 (100 g)-1]. Whereas the microinjection of SNP into the NTS increased splenic blood flow from 127 +/- 25 to 188 +/- 27 (P < 0.01) and renal blood flow from 346 +/- 28 to 371 +/- 26 ml min-1 (100 g) (P < 0.05) and decreased splenic vascular resistance from 0.77 +/- 0.13 to 0.44 +/- 0.06 (P < 0.01) and renal vascular resistance from 0.24 +/- 0.02 to 0.21 +/- 0.01 mmHg per [ml min-1 (100 g)-1] (P < 0.05). The blood flow of the liver was not significantly altered. Unilateral microinjection of NG-monomethyl-L-arginine, an inhibitor of the formation of NO from L-arginine, into the NTS (n = 10) did not significantly change the blood flows of all organs examined except for an increase in blood flow of the kidney. Unilateral microinjections of SNP into the area adjacent to the NTS (n = 9), of artificial cerebrospinal fluid into the NTS (n = 7) and of light-inactivated SNP into the NTS (n = 6) did not significantly alter the blood flows of all organs examined. These results suggest than the neurons in the NTS have a vasoconstrictor effect on the brain and spinal cord circulation and a vasodilator effect on the splenic and renal circulation. There is a regional qualitative differentiation of the blood flow responses between these organs during activation of the neurons in the NTS.
本研究旨在通过微量注射硝普钠（SNP，可自发释放一氧化氮（NO））来激活孤束核（NTS）中的神经元，以检测其对脾、肾、肝、脑及脊髓血流的影响，并研究这些器官之间血流变化的区域差异。采用氨基甲酸乙酯麻醉（1.5 g kg-1，腹腔注射）、麻痹并人工通气的大鼠，使用放射性微球（109Cd、51Cr和85Sr）同时测定这些器官的局部血流。向NTS单侧微量注射SNP（n = 9）可使脑血流从71±8（均值±标准误）降至54±6（P < 0.01），脊髓血流从58±8降至43±5 ml min-1（100 g）-1（P < 0.05），并使脑血管阻力从1.18±0.13升至1.48±0.15（P < 0.01），脊髓血管阻力从1.46±0.17升至1.80±0.16（P < 0.05）mmHg per [ml min-1（100 g）-1]。而向NTS微量注射SNP可使脾血流从127±25升至188±27（P < 0.01），肾血流从346±28升至371±26 ml min-1（100 g）（P < 0.05），并使脾血管阻力从0.77±0.13降至0.44±0.06（P < 0.01），肾血管阻力从0.24±0.02降至0.21±0.01 mmHg per [ml min-1（100 g）-1]（P < 0.05）。肝血流无显著变化。向NTS单侧微量注射L-精氨酸NO生成抑制剂NG-单甲基-L-精氨酸（n = 10），除肾血流增加外，对所有检测器官的血流均无显著影响。向NTS相邻区域单侧微量注射SNP（n = 9）、向NTS注射人工脑脊液（n = 7）以及向NTS注射光灭活的SNP（n = 6），对所有检测器官的血流均无显著影响。这些结果表明，NTS中的神经元对脑和脊髓循环具有血管收缩作用，对脾和肾循环具有血管舒张作用。在激活NTS中的神经元时，这些器官之间的血流反应存在区域性质的差异。
