CHARACTERIZATION OF THE BARORECEPTOR HEART-RATE REFLEX DURING DEVELOPMENT IN SPONTANEOUSLY HYPERTENSIVE RATS
CHARACTERIZATION OF THE BARORECEPTOR HEART-RATE REFLEX DURING DEVELOPMENT IN SPONTANEOUSLY HYPERTENSIVE RATS
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DOI：
10.1111/j.1440-1681.1992.tb00509.x
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发表时间：
1992-08-01
影响因子：
2.9
通讯作者：
ADAMS, MA
中科院分区：
文献类型：
--
作者：
HEAD, GA;ADAMS, MA
1. 我们研究了体重匹配的有意识自发性高血压大鼠（SHR）和正常Wistar-Kyoto大鼠（WKY）在发育过程中的压力受体-心率（HR）反射。甲拉托品迷走神经阻断前后平均动脉压（MAP）的梯度稳态变化和相应的HR反应符合s型logistic函数。在6周龄时，由于MAP- hr关系的曲率增加，SHR的MAP比WKY高17%，并且与WKY相比，气压反射增益（斜率）增加。此时两株的HR范围（上下HR平台之差）相似。从9-14周龄开始，由于HR范围的相应改变，WKY的压力反射增益逐渐增加，SHR的压力反射增益逐渐减少。到20周时，由于HR范围低37%，SHR的压力反射增益比WKY低23%。两种品系在任何年龄的压力反射交感神经成分均无差异，提示压力反射特性的改变仅限于心迷走神经。4-9周依那普利预处理可使SHR第14周和第20周的高血压降低38%，并消除两种菌株之间的压力感受器- hr反射差异。这些研究表明，SHR在发育过程中压力感受器-心率反射的主要变化是对血压变化作出反应的最大迷走神经容量的减少。这种影响在高血压发病后出现，并在生命早期通过抗高血压治疗加以预防。缺乏对心脏交感神经成分的影响表明，改变的动脉压力感受器传入并非不可能负责。
1. We have examined the baroreceptor-heart rate (HR) reflex in weight-matched conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats during development.2. Graded steady-state changes in mean arterial pressure (MAP) and the corresponding HR responses before and after vagal blockade with methylatropine were fitted to an S-shaped logistic function.3. At 6 weeks of age, SHR had a 17% higher MAP than WKY and an increased baroreflex gain (slope) compared with WKY due to an increased curvature of the MAP-HR relationship. The HR range (the difference between the upper and lower HR plateaus) was similar in the two strains at this time.4. From 9-14 weeks of age, the baroreflex gain progressively increased in WKY and decreased in SHR due to corresponding alterations in HR range.5. By 20 weeks the baroreflex gain was 23% lower in SHR than WKY due to a 37% lower HR range.6. There were no differences between the two strains in the sympathetic component of the baroreflex at any age, suggesting that the changes to baroreflex properties were confined to the cardiac vagus.7. Pretreatment with enalapril from 4-9 weeks reduced the hypertension of SHR at 14 and 20 weeks by 38% and abolished all baroreceptor-HR reflex differences between the two strains.8. These studies suggest that the major alteration to the baroreceptor-heart rate reflex in the SHR during development was a reduction in the maximum vagal capacity to respond to changes in blood pressure. This effect developed after the onset of hypertension and was prevented by antihypertensive treatment early in life. The lack of effect on the cardiac sympathetic component suggests that altered arterial baroreceptor afferents are not unlikely to be responsible.