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

Manja Reimann, Mark Hamer, Nicolaas T. Malan, Markus P. Schlaich, Gavin W. Lambert, Tjalf Ziemssen, Rainer H. Boeger, Leoné Malan

Research output: Contribution to journalArticle

12 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)751-758
Number of pages8
JournalPsychosomatic Medicine
Volume75
Issue number8
DOIs
Publication statusPublished - 2013
Externally publishedYes

Fingerprint Dive into the research topics of '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'. Together they form a unique fingerprint.

Cite this