Swimming training improves cardiovascular autonomic dysfunctions and prevents renal damage in rats fed a high‐sodium diet from weaning

Abstract

High sodium intake is an important factor associated with hypertension. High-sodium intake with exercise training can modify homeostatic hydro-electrolytic balance, but the effects of this association are mostly unknown. In this study, we sought to investigate the effects of swimming training (ST) on cerebrospinal fluid (CSF) Na + concentration, sympathetic drive, blood pressure (BP) and renal function of rats fed a 0.9% Na + (equivalent to 2% NaCl) diet with free access to water for 22 weeks after weaning. Male Wistar rats were assigned to two cohorts: (1) fed standard diet (SD) and (2) fed high-sodium (HS) diet. Each cohort was further divided into trained and sedentary groups. ST normalised BP levels of HS rats as well as the higher sympathetically related pressor activity assessed by pharmacological blockade of ganglionic transmission (hexamethonium). ST preserved the renal function and attenuated the glomerular shrinkage elicited by HS. No change in blood volume was found among the groups. CSF [Na + ] levels were higher in sedentary HS rats but were reduced by ST. Our findings showed that ST effectively normalised BP of HS rats, independent of its effects on hydro-electrolytic balance, which might involve neurogenic mechanisms regulated by Na + levels in the CSF as well as renal protection.

Acute effects of different Tai Chi practice protocols on cardiac autonomic modulation

“…In the case of exercise, stimulation of the heart activates physical and chemical receptors in the body's internal organs 40 . These receptors transmit nerve impulses to higher brain centers, leading to the activation of glutamatergic and gamma-aminobutyric nerves in specific regions like the nucleus solitarius, nucleus suspensus, ventral lateral nucleus of the medulla oblongata, and ventral lateral nucleus of the medulla caudalis 45 . This cascade ultimately results in an increase in norepinephrine secretion in the sympathetic ganglion, leading to heightened sympathetic activity and reduced parasympathetic activity 46 .…”

Short exposure to high salt in drinking solution leads to a cardiovascular phenotype of hypertension without changes in the blood volume of rats

“…After 30 min, 1 ml of blood was sampled from the femoral artery catheter (Figure 1 ). The Evan's Blue protocol has been described elsewhere (de Souza et al., 2021 ; Radu & Chernoff, 2013 ), but briefly, the concentration of Evan's Blue in the plasma was determined spectrophotometrically (Femto 6000 Plus) at a wavelength of 620 nm against a plasma blank from an untreated animal. The volumes injected or withdrawn were considered in the final accounts of circulating volume.…”

“…Collection of cerebrospinal fluid and blood and measurements of osmolality, Na + and K + In order to standardize the body fluid balance among groups the collections of cerebrospinal fluid (CSF) and blood samples were performed in all groups of animals deprived of food and liquid for 5 h (EU n = 4 or 5, SL n = 6 and WD n = 6; Figure 1). The CSF and blood samples were collected in animals under general anaesthesia, as previously described (de Souza et al, 2021;Gomes et al, 2017). Briefly, animals were placed in a stereotaxic apparatus, and the occipital muscles were removed to reach the atlanto-occipital membrane.…”

Aerobic exercise training prevents impairment in renal parameters and in body composition of rats fed a high sucrose diet

“…Collected material— right kidneys; Stage and calculation— as described by others [ 20 , 21 ]. Equipment— light microscope (Leica DM5000).…”