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Psychosom Med. 2013 Oct;75(8):751-8. doi: 10.1097/PSY.0b013e3182a3e465. Epub 2013 Aug 19.

Effects of acute and chronic stress on the L-arginine nitric oxide pathway in black and white South Africans: the sympathetic activity and ambulatory blood pressure in Africans study.

Author information

1
Autonomic and Neuroendocrinological Laboratory Dresden, Department of Neurology, University Hospital Carl Gustav Carus at the Dresden University of Technology, Fetscherstr. 74, 01307 Dresden, Germany. manja.reimann@uniklinikum-dresden.de.

Abstract

OBJECTIVE:

This study investigated the impact of stress on effectors of the L-arginine/nitric oxide (NO) system including the endogenous inhibitor asymmetric dimethylarginine (ADMA).

METHODS:

Black (n = 168) and white (n = 206) South African teachers were exposed to a mental and a physical stressor for 1 minute, respectively. Serum samples for determination of l-arginine, NO metabolites, ADMA, and symmetric dimethylarginine (SDMA) were obtained at rest and during stress exposure. Perception of task stressfulness was assessed on a 7-point Likert scale, and psychological distress was estimated by the General Health Questionnaire.

RESULTS:

Black South Africans exhibited higher resting levels of NO metabolites (adjusted mean [standard error of the mean] = 11.3 [1.3] versus 3.9 [1.1] μmol/l, p < .001) but lower circulating ADMA (0.62 [0.02] versus 0.70 [0.02] μmol/l, p = .004) and SDMA (0.41 [0.01] versus 0.53 [0.01] μmol/l, p < .001) than did white South Africans. Ethnicity-by-psychological distress interaction was observed for resting levels of ADMA (p = .002), SDMA (p = .038), and L-arginine (p = .048). Ethnic differences in responses to experimental stress were evident for NO metabolites (blacks versus whites: 5.94 [1.55] versus -0.74 [1.25] μmol/l, p = .004) and SDMA (blacks versus whites: -0.02 [0.01] versus 0.02 [0.01] μmol/l, p = .004). Ethnicity-by-psychological distress interaction for stress responses was found for l-arginine/ADMA ratio (p = .027).

CONCLUSIONS:

The l-arginine/NO system is affected by psychosocial distress with higher susceptibility in black South Africans. This interaction may contribute to the higher cardiovascular disease risk in black South Africans.

KEYWORDS:

African; asymmetric dimethylarginine; cold pressor test; distress; l-arginine/nitric oxide pathway

PMID:
23960161
DOI:
10.1097/PSY.0b013e3182a3e465
[Indexed for MEDLINE]

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