Interactions of plasma osmolality with arterial and central venous pressures in control of sympathetic activity and heart rate in humans

被引:56
作者
Charkoudian, N
Eisenach, JH
Joyner, MJ
Roberts, SK
Wick, DE
机构
[1] Mayo Clin, Dept Physiol & Biomed Engn, Coll Med, Dept Anesthesiol, Rochester, MN 55905 USA
[2] Mayo Clin, Gen Clin Res Ctr, Coll Med, Rochester, MN 55905 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY | 2005年 / 289卷 / 06期
关键词
baroreflex; sympathetic nervous system; hydration; plasma volume;
D O I
10.1152/ajpheart.00601.2005
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Plasma osmolality alters control of sympathetic activity and heart rate in animal models; however, it is unknown whether physiological increases in plasma osmolality have such influences in humans and what effect concurrent changes in central venous and/or arterial pressures may have. We tested whether physiological increases in plasma osmolality (similar to those during exercise dehydration) alter control of muscle sympathetic nerve activity (MSNA) and heart rate (HR) in humans. We studied 17 healthy young adults (7 women, 10 men) at baseline and during arterial pressure (AP) transients induced by sequential injections of nitroprusside and phenylephrine, under three conditions: control (C), after 1 ml/kg intravenous hypertonic saline (HT1), and after 2 ml/kg hypertonic saline (HT2). We continuously measured HR, AP, central venous pressure (CVP; peripherally inserted central catheter) and MSNA ( peroneal microneurography) in all conditions. Plasma osmolality increased from 287 +/- 1 mosmol/kg in C to 290 +/- 1 mosmol/kg in HT1 ( P < 0.05) but did not increase further in HT2 ( 291 +/- 1 mosmol/kg; P > 0.05 vs. C). Mean AP and CVP were similar between C and HT1, but both increased slightly in HT2. HR increased slightly but significantly during both HT1 and HT2 vs. C (P < 0.05). Sensitivity of baroreflex control of MSNA was significantly increased vs. C in HT1 [- 7.59 +/- 0.97 (HT1) vs. - 5.85 +/- 0.63 (C) arbitrary units (au) (.) beat(-1) (.) mmHg(-1); P < 0.01] but was not different in HT2(- 6.55 +/- 0.94 au (.) beat(-1) (.) mmHg(-1)). We conclude that physiological changes in plasma osmolality significantly alter control of MSNA and HR in humans, and that this influence can be modified by CVP and AP.
引用
收藏
页码:H2456 / H2460
页数:5
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