DIETARY NA AND BAROREFLEX MODULATION OF BLOOD-PRESSURE AND RSNA IN NORMOTENSIVE VS SPONTANEOUSLY HYPERTENSIVE RATS

被引:42
作者
HUANG, BS [1 ]
LEENEN, FHH [1 ]
机构
[1] UNIV OTTAWA,INST HEART,HYPERTENS UNIT,OTTAWA K1Y 4E9,ON,CANADA
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1994年 / 266卷 / 02期
关键词
RENAL SYMPATHETIC NERVE ACTIVITY; ARTERIAL BAROREFLEXES; SINOAORTIC DENERVATION;
D O I
10.1152/ajpheart.1994.266.2.H496
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
Different changes in baroreflex control of the circulation have been postulated to play a role in the different blood pressure (BP) effects of dietary sodium in normotensive vs. genetically hypertensive rats. We therefore evaluated in young Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR), with or without chronic sinoaortic denervation (SAD), the effects of low, regular, and high dietary sodium intake from 4 to 8 wk of age on BP and baroreflex function. The latter was assessed by changes in renal sympathetic nerve activity (RSNA) and heart rate in response to (de)pressor agents. In SHR, the above range of sodium caused a marked change in resting BP, somewhat more in intact (48 mmHg) vs. SAD (36 mmHg) rats. In contrast, in WKY this range of sodium intake caused only a minor (7 mmHg) change in resting BP of intact WKY but a significant (16 mmHg) change in WKY with SAD, mainly due to an increase in BP on high sodium. In intact WKY increasing dietary sodium from low to regular to high caused stepwise increases in the gain of the RSNA-BP reflex, whereas in intact SHR only an increase from low to regular sodium intake increased the gain. After SAD, the gain of the RSNA-BP reflex was very low, and no longer affected by dietary sodium in either strain. These data suggest that in WKY a sensitization in arterial baroreflex control of RSNA prevents a sodium-induced increase in BP. Different effects of high sodium on arterial baroreceptor input appear to account in part for the between-strain difference in BP sensitivity to sodium of WKY vs. SHR.
引用
收藏
页码:H496 / H502
页数:7
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