This study examines the effect of angiotensin converting enzyme inhibition and dietary salt on physiological responses to behavioral stressors. It is difficult to tease apart the roles of the sympathetic nervous system, the renin-angiotensin system, and dietary salt. For instance, under low salt conditions, there is activation of both the sympathetic nervous system and the renin- angiotensin system. As a result, observing an increased pressor response to stressors in patients on high salt intake is not straightforward. A beginning way to understand this system is to block production of angiotensin II with an angiotensin covering enzyme inhibitor (captopril). Thirty hypertensive and 30 normotensive white men will be admitted for two 5-day hospitalizations on a Clinical Research Center while they consume a low salt diet (10 meq/d). These subjects will participate in a randomized crossover design employing either placebo on the initial hospitalization or captopril. Patients will be studied at rest, while they are exposed to behavioral stressors, and during infusions of norepinephrine. The following physiological variables will be monitored: blood pressure, heart rate, plasma and urinary catecholamines, renin, aldosterone, angiotensin II, atrial natriuretic factor, urinary sodium, and the slope of the dose response curve relating infused norepinephrine to blood pressure. The investigators will also have obtained data from another project on an additional 60 subjects, studied on the same reactivity protocol, but who are hospitalized on a high salt diet (200 meq/d). The reactivity of these subjects will be compared to that elicited by other subjects on a combination of salt depletion plus captopril. Thus the effects of salt intake will be studied while blocking the activation of the renin-angiotensin system on the low salt diet.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL040102-05
Application #
3357194
Study Section
Special Emphasis Panel (SRC (08))
Project Start
1989-09-29
Project End
1993-11-30
Budget Start
1992-08-01
Budget End
1993-11-30
Support Year
5
Fiscal Year
1991
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Type
Schools of Medicine
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Mills, Paul J; von Kanel, Roland; Norman, Daniel et al. (2007) Inflammation and sleep in healthy individuals. Sleep 30:729-35
Mills, Paul J; Kennedy, Brian P; Loredo, Jose S et al. (2006) Effects of nasal continuous positive airway pressure and oxygen supplementation on norepinephrine kinetics and cardiovascular responses in obstructive sleep apnea. J Appl Physiol 100:343-8
Mills, Paul J; Dimsdale, Joel E (2004) Sleep apnea: a model for studying cytokines, sleep, and sleep disruption. Brain Behav Immun 18:298-303
Mills, P J; Dimsdale, J E; Ancoli-Israel, S et al. (1998) The effects of hypoxia and sleep apnea on isoproterenol sensitivity. Sleep 21:731-5
Mills, P J; Berry, C C; Dimsdale, J E (1997) Race affects the decline in blood pressure with hospitalization. Am J Hypertens 10:1091-6
Gillin, J L; Mills, P J; Nelesen, R A et al. (1996) Race and sex differences in cardiovascular recovery from acute stress. Int J Psychophysiol 23:83-90
Mills, P J; Dimsdale, J E; Nelesen, R A et al. (1996) Psychologic characteristics associated with acute stressor-induced leukocyte subset redistribution. J Psychosom Res 40:417-23
Mills, P J; Dimsdale, J E (1996) The effects of acute psychologic stress on cellular adhesion molecules. J Psychosom Res 41:49-53
Mills, P J; Ziegler, M G; Nelesen, R A et al. (1996) The effects of the menstrual cycle, race, and gender on adrenergic receptors and agonists. Clin Pharmacol Ther 60:99-104
Mills, P J; Haeri, S L; Dimsdale, J E (1995) Temporal stability of acute stressor-induced changes in cellular immunity. Int J Psychophysiol 19:287-90

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