title: The 894G>T endothelial nitric oxide synthase genetic polymorphism affects hemodynamic responses to mental stress performed before and after exercise.
abstract: Nitric oxide is the primary mediator of vasodilation during mental stress. Since genetic polymorphisms in the nitric oxide synthase (eNOS) gene seem to impair the production of NO, this study aimed to evaluate the effect of an exercise bout on hemodynamic responses to mental stress in subjects with the 894G>T polymorphism of eNOS. Subjects without (wild-type group; n = 16) or with (polymorphic-type group; n = 19) the 894G>T polymorphism underwent a mental stress challenge before and after a maximal cardiopulmonary exercise test. Blood pressure was measured by auscultation and forearm blood flow by venous occlusion plethysmography. The groups were similar regarding anthropometric, metabolic, resting blood pressure and exercise variables. Before exercise, systolic blood pressure response during mental stress was higher in the polymorphic-type group (∆wild-type: 8.0 ± 2.0% vs. ∆polymorphic-type: 12.5 ± 1.8%, P = 0.01), while the increase in forearm vascular conductance was similar between the groups (∆wild-type 90.8 ± 26.4% vs. ∆polymorphic-type: 86.3 ± 24.1%, P = 0.44). After exercise, the systolic blood pressure at baseline and during mental stress was lower than before exercise in the whole group (P < 0.05), but the pressure response during mental stress was still higher in the polymorphic-type group (∆wild-type: 5.8 ± 1.5% vs. ∆polymorphic-type: 10.2 ± 1.4%, P = 0.01). The increase in forearm vascular conductance was inhibited only in the polymorphic-type group (∆before exercise 86.3 ± 24.1% vs. ∆after exercise: 41.5 ± 12.6%, P = 0.04). In conclusion, these results suggest the 894G>T eNOS polymorphism is associated with altered hemodynamic responses to mental stress both before and after a single bout of dynamic exercise with potential clinical implications.
authors.affiliation: Laboratory of Exercise Sciences (LACE), Fluminense Federal University, Rua Hernani Pires de Melo, São Domingos, 101/106, Niterói, RJ, Brazil.
authors.forename: Natália Galito
authors.initials: NG
authors.lastname: Rocha
authors.forename: Fabricia Junqueira
authors.initials: FJ
authors.lastname: Neves
authors.forename: Bruno Moreira
authors.initials: BM
authors.lastname: Silva
authors.forename: Allan Robson Kluser
authors.initials: AR
authors.lastname: Sales
authors.forename: Antonio Claudio
authors.initials: AC
authors.lastname: Nóbrega
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015444:Exercise / Q000502:physiology / Q000523:psychology; D005080:Exercise Test; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006439:Hemodynamics / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000502:physiology*; D013315:Stress, Psychological / Q000235:genetics* / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult
chemical_list: C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III