[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to investigate the effect of swimming on the cardiac morphological and
hemodynamic changes in rats with hypertension induced by L-NAME.. Forty Wistar rats were divided into
four groups: sedentary control (SC), trained control (TC), sedentary with L-NAME (LS) and trained with LNAME
(LT). The animals in the training groups performed swimming lasting up to 60 min for four weeks.
Animals in the L-NAME groups received 20 mg.kg-1 during four weeks. The results showed that animals in
the LS group had higher mean arterial pressure (136.6±5.1 mmHg) compared to CS (107.1±1.8 mmHg).
The LT group showed significant reductions in mean arterial pressure compared to LS (121.2±1.4 and
136.6±5.1 mmHg, respectively). On the other hand, the LT group animals still remained hypertensive
compared to CT group (121.0±1.4 and 107.1±1.8 mmHg respectively). In relation to HR, was observed
resting bradycardia for the trained animals. The groups CS and CT showed no changes in relative and
absolute weight of the heart. An increase in the absolute weight of the heart to the LS group compared to
the CS and also observed an increase in the relative and absolute weight for the LT group compared to
CT. Histologic analysis showed that exercise training can reduce the amount of damage caused by chronic
administration of L-NAME. In conclusion, we observed that mild exercise was effective in reducing mean
arterial pressure in hypertensive rats. Additionally, exercise training did not induced cardiac hypertrophy,
but the L-NAME increase the absolute and relative weight of the heart in sedentary and trained rats.
[Show abstract][Hide abstract] ABSTRACT: Purpose: This study aimed to analyze the hemodynamic and cardiac effects of direct renin inhibitor (DRI) treatment and swimming training in hypertensive rats. Methods: Seventy-seven rats were divide into eight groups: sedentary normotensive (SN), trained normotensive (TN), sedentary normotensive treated with DRI (SN_DRI), trained normotensive treated with DRI (TN_DRI), sedentary hypertensive (SH), trained hypertensive (TH), sedentary hypertensive treated with DRI (SH_DRI), trained hypertensive treated with DRI (TH_DRI). Swimming training occurred for up to 60 min, five times a week for four weeks. The hypertensive animals were treated with 20 mg ċ kg−1 ċ day−1 L-NAME for four weeks. Groups treated with DRI received 10 mg ċ kg−1 ċ day−1 of aliskiren for four weeks. After the treatment period, all the animals underwent femoral artery catheterization surgery for direct measurement of cardiovascular variables. Results: The SH group presented hypertension (136.4 ± 5.0 mmHg) compared to the SN (107.1 ± 1.7 mmHg). The TH group showed lower mean arterial pressure (MAP) than the SH (121.1 ± 1.3 mmHg), but the treatment with DRI did not attenuate hypertension (128.2 ± 4.9 mmHg). The analysis of collagen areas demonstrated that treatment with DRI may attenuate cardiac remodeling in situations of hypertension, in the condition of treatment alone or combined with physical training. Conclusion: Both interventions in combination may be more effective at reducing cardiovascular risk in hypertensive subjects.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to determine whether exercise training combined with beta-blocker treatment promotes additional cardiovascular benefits compared with either intervention on its own. For this we used 76 Wistar rats distributed among different groups: normotensive sedentary (NS), normotensive trained (NT), normotensive sedentary treated with beta-blocker (NS_BB), normotensive trained treated with beta-blocker (NT_BB), hypertensive sedentary (HS), hypertensive trained (HT), hypertensive sedentary treated with a beta-blocker (HS_BB), and hypertensive trained rats treated with beta-blocker (HT_BB). Exercise training consisted of 4 weeks of swimming for 60 min a day, 5 days a week. Hypertension was induced with l-NAME (4 weeks), whereas the control rats received saline, and both the control and test rats received nebivolol. The animals underwent surgery to directly record their blood pressure. The HS group showed higher mean arterial pressure (MAP) (P = 0.000), systolic arterial pressure (P = 0.000), and diastolic arterial pressure (P = 0.000) compared with NS. MAP was higher in the HS compared with the HT (P = 0.002), HS_BB (P = 0.018), and HT_BB (P = 0.015) groups. Hearts from the HS group had a higher percentage of collagen compared with the NS and HS_BB groups. The HT_BB and HT groups only had a higher percentage of cardiac collagen by comparison with the HS_BB group. The HT_BB group showed higher levels of macrophages and neutrophils by comparison with the HT and HS_BB groups. Thus, treatment with a beta-blocker combined with physical training was associated with increased cardiovascular benefits over either intervention alone.
Canadian Journal of Physiology and Pharmacology 03/2014; 92(3):234-42. DOI:10.1139/cjpp-2013-0186 · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The literature suggests that both obesity and hypertension are associated with increased sympathetic nerve activity. In the present study we evaluated the renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) in hyperadipose rats induced by neonatal administration of monosodium glutamate (MSG). Neonatal Wistar male rats were injected with MSG (4 mg/g body weight ID) or equimolar saline (control) for 5 days. At 90th day, all rats were anesthetized (urethane 1.4 g/kg) and prepared for MAP, HR and renal sympathetic nerve activity recordings. The anesthetized MSG rats presented baseline hypertension and increased baseline RSNA compared with control. Our results suggest the involvement of the renal sympathetic nervous system in the physiopathology of the MSG obesity.
[Show abstract][Hide abstract] ABSTRACT: We aimed to examine the cardiovascular function by tonic and baroreflex alterations in obese rats induced by monosodium glutamate (MSG). Neonatal male Wistar rats were injected with MSG (4 mg/g body weight) or equimolar saline (control, C). At 90 days, all rats were anesthetized for catheterization of the femoral artery for mean arterial pressure (MAP) and heart rate (HR) recordings in the conscious state. After baseline, we performed IV treatment with hexamethonium (25 mg/kg), or atropine (1 mg/kg) or propranolol (3 mg/kg). We also performed the spectral analysis of heart rate variability (HRV) and baroreflex sensitivity. Baseline comparison showed that obese rats are hypertensive compared with control (C=110±2 mmHg; MSG=: 123±3 mmHg, P<0.05). After ganglionic blockade with hexamethonium the differences in MAP between control and obese rats disappeared. Beta adrenergic blockade with propranolol induced a greater decrease in heart rate compared with control. The analysis of HRV showed that obese rats have increased modulation by both components of the autonomic nervous system compared with control rats. The baroreflex gain showed increased sensitivity for the parasympathetic component in the obese rats (C=-2.41±0.25; MSG=-3.34±0.23 bpm/mmHg) compared with control. Our data suggest that both components of autonomic cardiac tonus and the parasympathetic component of the baroreflex sensitivity are increased in the MSG obese rat. It is possible that the parasympathetic alterations observed in these MSG obese rats may have originated from central areas of cardiovascular control.