eNOS gene haplotype is indirectly associated with the recovery of cardiovascular autonomic modulation from exercise

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene decrease expression and activation of eNOS in vitro, which is associated with lower post-exercise increase in vasodilator reactivity in vivo. However, it is unknown whether such polymorphisms are associated with other eNOS-related phenotypes during recovery from exercise. Therefore, we investigated the impact of an eNOS haplotype containing polymorphic alleles at loci 786 and 894 on the recovery of cardiovascular autonomic function from exercise. Sedentary, non-obese, healthy subjects were enrolled [n = 107, age 32 +/- 1 years (mean +/- SEM)]. Resting autonomic modulation (heart rate variability, systolic blood pressure variability, and spontaneous baroreflex sensitivity) and vascular reactivity (forearm hyperemic response post-ischemia) were assessed at baseline, 10, 60, and 120 min after a maximal cardiopulmonary exercise test. Besides, autonomic function was assessed by heart rate recovery (HRR) immediately after peak exercise. Haplotype analysis showed that vagal modulation (i.e., HF n.u.) was significantly higher, combined sympathetic and vagal modulation (i.e., LF/HF) was significantly lower and total blood pressure variability was significantly lower post-exercise in a haplotype containing polymorphic alleles (H2) compared to a haplotype with wild type alleles (H1). HRR was similar between groups. Corroborating previous evidence, H2 had significantly lower post-exercise increase in vasodilator reactivity than HI. in conclusion, a haplotype containing polymorphic alleles at loci -786 and 894 had enhanced recovery of autonomic modulation from exercise, along with unchanged HRR, and attenuated vasodilator reactivity. Then, these results suggest an autonomic compensatory response of a direct deleterious effect of eNOS polymorphisms on the vascular function. (C) 2014 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Brazilian Funding Agency for Studies and Projects (FINEP)Univ Fed Fluminense, Lab Exercise Sci, Dept Physiol & Pharmacol, Niteroi, RJ, BrazilUniversidade Federal de São Paulo, Sect Exercise Physiol, Dept Physiol, São Paulo, BrazilUniversidade Federal de São Paulo, Sect Exercise Physiol, Dept Physiol, São Paulo, BrazilCNPq: 307251/2009-8CNPq: 501783/2010-5CNPq: 481160/2008-6FAPERJ: E-26/101.980/2010CAPES: 0723-09-6Brazilian Funding Agency for Studies and Projects (FINEP): FEC 2400Web of Scienc