Abnormalities of Cardiac Sympathetic Nerve Ending Functions in Essential Hypertension

为探讨原发性高血压患者交感神经末梢功能是否受损，我们应用透析技术对麻醉的SHR和WKY大鼠的左心室心肌进行了研究（20周），并监测心肌间质去甲肾上腺素（NE）和二羟苯乙二醇（DHPG）水平，作为心脏交感神经末梢NE释放和神经元内NE代谢的指标。而SHR的平均动脉压、湿心重、血浆NE浓度和血浆DHPG浓度均高于WKY，心肌间质NE水平与WKY无显著差异，但高K^+和酪胺引起的间质NE反应低于WKY。提示SHR心交感神经末梢NE释放功能受损。心肌间质DHPG水平和去甲丙咪嗪（NE再摄取抑制剂）诱导的心肌缺血无差异。 关于我们 SHR和WKY间质NE反应。这些结果表明，SHR心脏交感神经末梢的NE重摄取和神经元内NE代谢功能是完整的。然后，我们将重点放在骨骼肌交感神经支配阻力动脉作为高血浆NE和DHPG水平的原因。采用透析技术对麻醉的SHR和WKY大鼠（20周）的左股骨骼肌进行检测，以骨骼肌间质NE和DHPG水平作为骨骼肌交感神经末梢NE释放和神经元内NE代谢的指标，SHR大鼠骨骼肌间质NE水平高于WKY大鼠。高K^+和酪胺诱导的SHR间质NE反应高于WKY。这些结果表明，在SHR骨骼肌交感神经末梢的NE释放功能增强，这种增强有助于高血浆NE水平。SHR骨骼肌间质DHPG水平高于WKY，但DHPG/NE比值及去甲丙咪嗪诱导的间质NE反应在SHR和WKY间无差异。这些结果表明，自发性高血压大鼠骨骼肌交感神经末梢的NE重摄取和神经元内NE代谢功能是完整的。少

To elucidate whether sympathetic nerve ending functions are impaired in essential hypertension, we applied dialysis technique to the left ventricular myocardium of anesthetized SHR and WKY rats (20 weeks) and monitored myocardial interstitial norepinephrine(NE) and dihydroxyphenylglycol(DHPG) levels as indexes of NE release and intraneuronal NE metabolism on cardiac sympathetic nerve endings.There was no difference in heart rate between SHR and WKY, but the mean arterial pressure, the weight of wet heart, plasma NE concentration, and plasma DHPG concentration in SHR were higher than those in WKY.There was no difference in myocardial interstitial NE levels between SHR and WKY, but high K^+- and tyramine-induced interstitial NE responses in SHR were lower than those in WKY. These results suggest that NE release function on cardiac sympathetic nerve endings is impaired in SHR. There was no difference in myocardial interstitial DHPG levels and desipramine (NE reuptake inhibitor) -induced i … More nterstitial NE responses between SHR and WKY. These results suggest that NE reuptake and intraneuronal NE metabolic functions on cardiac sympathetic nerve endings are intact in SHR.Then, we focused on skeletal muscle sympathetic nerves innervating resistant arteries as causes of high plasma NE and DHPG levels. We applied dialysis technique to the left femoral skeletal muscle of anesthetized SHR and WKY rats (20 weeks) and monitored skeletal muscle interstitial NE and DHPG levels as indexes of NE release and intraneuronal NE metabolism on skeletal muscle sympathetic nerve endings.Skeletal muscle interstitial NE levels in SHR were higher than those in WKY. High K^+- and tyramine-induced interstitial NE responses in SHR were higher than those in WKY. These results suggest that NE release function on skeletal muscle sympathetic nerve endings is enhanced in SHR and this enhancement contributes to high plasma NE levels. Skeletal muscle interstitial DHPG levels in SHR were higher than WKY, but there was no difference in DHPG/NE ratios and desipramine-induced interstitial NE responses between SHR and WKY. These results suggest that NE reuptake and intraneuronal NE metabolic functions on skeletal muscle sympathetic nerve endings are intact in SHR. Less