Koyama S, Fujita T, Uematsu H, Shibamoto T, Aibiki M, Kojima S
Department of Physiology, Shinshu University School of Medicine, Nagano, Japan.
Am J Physiol. 1990 Feb;258(2 Pt 2):R383-7. doi: 10.1152/ajpregu.1990.258.2.R383.
We have examined baroreceptor regulation of renal nerve activity (RNA) during anaphylactic hypotension that affects renal nerve activity. In anesthetized dogs, mean blood pressure (MBP), heart rate (HR), and RNA were simultaneously measured. To test for a normally functioning baroreceptor reflex in each animal, a transient hypotension was induced by an intravenous injection of sodium nitroprusside (4 micrograms/kg). Nitroprusside produced a reflex increase in RNA (+63 +/- 12% at -20 mmHg and +139 +/- 8% at -40 mmHg) and HR (+13 +/- 1 beats/min at -20 mmHg and +21 +/- 2 beats/min at -40 mmHg). However, intravenous administration of Ascaris suum antigen in animals with an intact neuraxis caused a decrease in RNA (-15 +/- 14% at -20 mmHg and -42 +/- 11% at -40 mmHg blood pressure during the antigen-induced hypotension) in parallel with a fall in systemic blood pressure. HR responses were -5 +/- 2 beats/min at -20 mmHg and -10 +/- 1 beats/min at -40 mmHg during the hypotension induced by the antigen. In animals with combined denervation of the carotid sinus and vagal nerves, HR did not change significantly during anaphylactic hypotension. However, a decrease in RNA remained (-60 +/- 4% at -20 mmHg and -72 +/- 4% at -40 mmHg of hypotension). The decrease in RNA after antigen administration was significantly greater after denervation than in animals with an intact neuraxis. These results indicate that systemic baroreceptor reflex control of RNA is reduced during anaphylactic hypotension. Impaired reflex control of sympathetic nerve activity may result from an impairment of sympathetic outflow through the central nervous system.
我们研究了在影响肾神经活动的过敏性低血压期间压力感受器对肾神经活动（RNA）的调节。在麻醉的狗身上，同时测量平均血压（MBP）、心率（HR）和RNA。为了测试每只动物的压力感受器反射功能是否正常，通过静脉注射硝普钠（4微克/千克）诱导短暂性低血压。硝普钠使RNA反射性增加（在血压为-20 mmHg时增加63±12%，在血压为-40 mmHg时增加139±8%）以及HR增加（在血压为-20 mmHg时增加13±1次/分钟，在血压为-40 mmHg时增加21±2次/分钟）。然而，向神经轴完整的动物静脉注射猪蛔虫抗原会导致RNA降低（在抗原诱导的低血压期间，血压为-20 mmHg时降低15±14%，血压为-40 mmHg时降低42±11%），同时全身血压下降。在抗原诱导的低血压期间，HR反应在血压为-20 mmHg时为-5±2次/分钟，在血压为-40 mmHg时为-10±1次/分钟。在颈动脉窦和迷走神经联合去神经支配的动物中，过敏性低血压期间HR无显著变化。然而，RNA仍会降低（在血压为-20 mmHg时降低60±4%，在血压为-40 mmHg时降低72±4%）。去神经支配后给予抗原后RNA的降低比神经轴完整的动物显著更大。这些结果表明，在过敏性低血压期间，压力感受器对RNA的全身反射控制减弱。交感神经活动反射控制受损可能是由于通过中枢神经系统的交感神经传出受损所致。
