title: Increased Nitric Oxide Bioavailability and Decreased Sympathetic Modulation Are Involved in Vascular Adjustments Induced by Low-Intensity Resistance Training.
abstract: Resistance training is one of the most common kind of exercise used nowadays. Long-term high-intensity resistance training are associated with deleterious effects on vascular adjustments. On the other hand, is unclear whether low-intensity resistance training (LI-RT) is able to induce systemic changes in vascular tone. Thus, we aimed to evaluate the effects of chronic LI-RT on endothelial nitric oxide (NO) bioavailability of mesenteric artery and cardiovascular autonomic modulation in healthy rats. Wistar animals were divided into two groups: exercised (Ex) and sedentary (SED) rats submitted to the resistance (40% of 1RM) or fictitious training for 8 weeks, respectively. After LI-RT, hemodynamic measurements and cardiovascular autonomic modulation by spectral analysis were evaluated. Vascular reactivity, NO production and protein expression of endothelial and neuronal nitric oxide synthase isoforms (eNOS and nNOS, respectively) were evaluated in mesenteric artery. In addition, cardiac superoxide anion production and ventricle morphological changes were also assessed. In vivo measurements revealed a reduction in mean arterial pressure and heart rate after 8 weeks of LI-RT. In vitro studies showed an increased acetylcholine (ACh)-induced vasorelaxation and greater NOS dependence in Ex than SED rats. Hence, decreased phenylephrine-induced vasoconstriction was found in Ex rats. Accordingly, LI-RT increased the NO bioavailability under basal and ACh stimulation conditions, associated with upregulation of eNOS and nNOS protein expression in mesenteric artery. Regarding autonomic control, LI-RT increased spontaneous baroreflex sensitivity, which was associated to reduction in both, cardiac and vascular sympathetic modulation. No changes in cardiac superoxide anion or left ventricle morphometric parameters after LI-RT were observed. In summary, these results suggest that RT promotes beneficial vascular adjustments favoring augmented endothelial NO bioavailability and reduction of sympathetic vascular modulation, without evidence of cardiac overload.
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Fabrício N
authors.initials: FN
authors.lastname: Macedo
authors.affiliation: Laboratory of Cardiovascular Biology and Oxidative Stress, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Thassio R R
authors.initials: TR
authors.lastname: Mesquita
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Vitor U
authors.initials: VU
authors.lastname: Melo
authors.affiliation: Department of Healthy Education, Estacio Faculty of Sergipe Aracaju, Brazil.
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Mota
authors.affiliation: Department of Healthy Education, Estacio Faculty of Sergipe Aracaju, Brazil.
authors.forename: Tharciano L T B
authors.initials: TL
authors.lastname: Silva
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Santana
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Larissa R
authors.initials: LR
authors.lastname: Oliveira
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Robervan V
authors.initials: RV
authors.lastname: Santos
authors.affiliation: Laboratory of Cardiovascular Biology and Oxidative Stress, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Miguel Dos Santos
authors.affiliation: Laboratory of Cardiovascular Biology and Oxidative Stress, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Sandra
authors.initials: S
authors.lastname: Lauton-Santos
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Marcio R V
authors.initials: MR
authors.lastname: Santos
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Andre S
authors.initials: AS
authors.lastname: Barreto
authors.affiliation: Laboratory of Cardiovascular Pharmacology, Department of Physiology, Federal University of Sergipe Sao Cristovao, Brazil.
authors.forename: Valter J
authors.initials: VJ
authors.lastname: Santana-Filho
keywords: autonomic nervous system; eNOS enzyme; endothelium-dependent relaxing factors; nNOS enzyme; nitric oxide; resistance training