Influence of plasma osmolality on baroreflex control of sympathetic activity

被引:31
作者
Wenner, Megan M.
Rose, William C.
Delaney, Erin P.
Stillabower, Michael E.
Farquhar, William B.
机构
[1] Univ Delaware, Dept Hlth Nutr & Exercise Sci, Newark, DE USA
[2] Univ Delaware, Coll Hlth Sci, Newark, DE USA
[3] Cardiovasc Res, Christiana Care Hlth Syst, Newark, DE USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY | 2007年 / 293卷 / 04期
关键词
baroreceptor; muscle sympathetic nerve activity; intravascular volume;
D O I
10.1152/ajpheart.01383.2006
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
The purpose of this study was to determine if plasma osmolality alters baroreflex control of sympathetic activity when controlling for a change in intravascular volume; we hypothesized that baroreflex control of sympathetic activity would be greater during a hyperosmotic stimulus compared with an isoosmotic stimulus when intravascular volume expansion was matched. Seven healthy subjects (25 +/- 2 yr) completed two intravenous infusions: a hypertonic saline infusion (HSI; 3% NaCl) and, on a separate occasion, an isotonic saline infusion (ISO; 0.9% NaCl), both at a rate of 0.15 ml . kg(-1) . min(-1). To isolate the effect of osmolality, comparisons between HSI and ISO conditions were retrospectively matched based on hematocrit; therefore, baroreflex control of sympathetic outflow was determined at 20 min of a HSI and 40 min of an ISO. Muscle sympathetic outflow (MSNA) was directly measured using the technique of peroneal microneurography; osmolality and blood pressure (Finometer) were assessed. The baroreflex control of sympathetic outflow was estimated by calculating the slope of the relationship between MSNA and diastolic blood pressure during controlled breathing. Plasma osmolality was greater during the HSI compared with the ISO (HSI: 292 +/- 0.9 mosmol/kg and ISO: 289 +/- 0.8 mosmol/ kg, P < 0.05). Hematocrits were matched (HSI: 39.1 +/- 1% and ISO: 39.1 +/- 1%, P > 0.40); thus, we were successful in isolating osmolality. The baroreflex control of sympathetic outflow was greater during the HSI compared with the ISO (HSI: -8.3 +/- 1.2 arbitrary units . beat(-1) . mmHg(-1) vs. ISO: -4.0 +/- 0.8 arbitrary units . beat(-1) . mmHg(-1), P = 0.01). In conclusion, when controlling for intravascular volume, increased plasma osmolality enhances baroreflex control of sympathetic activity in humans.
引用
收藏
页码:H2313 / H2319
页数:7
相关论文
共 35 条
[1]   Translation of salt retention to central activation of the sympathetic nervous system in hypertension [J].
Brooks, VL ;
Haywood, JR ;
Johnson, AK .
CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, 2005, 32 (5-6) :426-432
[2]   Increased osmolality of conscious water-deprived rats supports arterial pressure and sympathetic activity via a brain action [J].
Brooks, VL ;
Qi, Y ;
O'Donaughy, TL .
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 2005, 288 (05) :R1248-R1255
[3]   Depressed baroreflex sensitivity in patients with obstructive sleep apnea [J].
Carlson, JT ;
Hedner, JA ;
Sellgren, J ;
Elam, M ;
Gunnar, B .
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE, 1996, 154 (05) :1490-1496
[4]   Interactions of plasma osmolality with arterial and central venous pressures in control of sympathetic activity and heart rate in humans [J].
Charkoudian, N ;
Eisenach, JH ;
Joyner, MJ ;
Roberts, SK ;
Wick, DE .
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 2005, 289 (06) :H2456-H2460
[5]   Balance between cardiac output and sympathetic nerve activity in resting humans: role in arterial pressure regulation [J].
Charkoudian, N ;
Joyner, MJ ;
Johnson, CP ;
Eisenach, JH ;
Dietz, NA ;
Wallin, BG .
JOURNAL OF PHYSIOLOGY-LONDON, 2005, 568 (01) :315-321
[6]   Influence of increased central venous pressure on baroreflex control of sympathetic activity in humans [J].
Charkoudian, N ;
Martin, EA ;
Dinenno, FA ;
Eisenach, JH ;
Dietz, NM ;
Joyner, MJ .
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 2004, 287 (04) :H1658-H1662
[7]   Influences of hydration on post-exercise cardiovascular control in humans [J].
Charkoudian, N ;
Halliwill, JR ;
Morgan, BJ ;
Eisenach, JH ;
Joyner, MJ .
JOURNAL OF PHYSIOLOGY-LONDON, 2003, 552 (02) :635-644
[8]   Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure [J].
Chobanian, AV ;
Bakris, GL ;
Black, HR ;
Cushman, WC ;
Green, LA ;
Izzo, JL ;
Jones, DW ;
Materson, BJ ;
Oparil, S ;
Wright, JT ;
Roccella, EJ .
HYPERTENSION, 2003, 42 (06) :1206-1252
[9]   BAROREFLEX MODULATION OF SYMPATHETIC OUTFLOW DURING PHYSIOLOGICAL INCREASES OF VASOPRESSIN IN HUMANS [J].
EBERT, TJ ;
COWLEY, AW .
AMERICAN JOURNAL OF PHYSIOLOGY, 1992, 262 (05) :H1372-H1378
[10]  
ECKBERG DL, 1992, HUMAN BAROREFLEXES D