Effects of Chronic Cholinergic Stimulation Associated With Aerobic Physical Training on Cardiac Morphofunctional and Autonomic Parameters in Spontaneously Hypertensive Rats

Abstract We investigated in spontaneously hypertensive rats (SHR) the hemodynamic, cardiac morphofunctional, and cardiovascular autonomic adaptations after a protocol of aerobic physical training associated with chronic cholinergic stimulation. Fifty-four SRH were divided into two groups: trained and untrained. Afterward, each group was subdivided into three smaller groups: vehicle, treated with pyridostigmine bromide at 5mg/kg/day, and at 15mg/kg/day. The following protocols were assessed: echocardiography, autonomic double pharmacological blockade, analysis of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS). Physical training and pyridostigmine bromide reduced blood pressure and heart rate and increased vagal participation in cardiac tonic autonomic balance. Associated the responses were potentialized. Pyridostigmine bromide increased the oscillation of low frequency (LF:0.2-0.75Hz) and high frequency (HF:0.75-3Hz) of HRV. However, the association with physical training attenuated HF oscillations. Pyridostigmine bromide also increased LF oscillations of BPV. Both treatments promoted morphofunctional adaptations and associated increased the ejection volume, ejection fraction, cardiac output, and cardiac index. In conclusion, the association of pyridostigmine bromide and physical training promoted greater benefits in hemodynamic parameters and increase vagal influence on cardiac autonomic tonic balance. Nonetheless, pyridostigmine bromide alone seems to negatively affect BPV, while the association of treatment negatively influences HRV.

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Effects of chronic cholinergic stimulation associated with aerobic physical training on cardiac morphofunctional and autonomic parameters in spontaneously hypertensive rats

Scientific Reports ◽

10.1038/s41598-021-96505-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Camila B. Gardim ◽

Ana Catarine Veiga ◽

Bruno A. Aguilar ◽

Stella V. Philbois ◽

Hugo C. D. Souza

Keyword(s):

Physical Training ◽

Spontaneously Hypertensive Rats ◽

Baroreflex Sensitivity ◽

Low Frequency ◽

Pyridostigmine Bromide ◽

Cholinergic Stimulation ◽

Hypertensive Rats ◽

Spontaneously Hypertensive ◽

Treatment Groups ◽

Pharmacological Blockade

AbstractWe investigated hemodynamic, cardiac morphofunctional, and cardiovascular autonomic adaptations in spontaneously hypertensive rats (SHRs) after aerobic physical training associated with chronic cholinergic stimulation. Fifty-four SHRs were divided into two groups: trained and untrained. Each group was further subdivided into three smaller groups: vehicle, treated with pyridostigmine bromide at 5 mg/kg/day, and treated with pyridostigmine bromide at 15 mg/kg/day. The following protocols were assessed: echocardiography, autonomic double pharmacological blockade, heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS). Physical training and pyridostigmine bromide reduced BP and HR and increased vagal participation in cardiac autonomic tonic balance. The associated responses were then potentialized. Treatment with pyridostigmine bromide increased HRV oscillation of both low frequency (LF: 0.2–0.75 Hz) and high frequency (HF: 0.75–3 Hz). However, the association with physical training attenuated HF oscillations. Additionally, treatment with pyridostigmine bromide also increased LF oscillations of BPV. Both treatment groups promoted morphofunctional adaptations, and associated increased ejection volume, ejection fraction, cardiac output, and cardiac index. In conclusion, the association of pyridostigmine bromide and physical training promoted greater benefits in hemodynamic parameters and increased vagal influence on cardiac autonomic tonic balance. Nonetheless, treatment with pyridostigmine bromide alone seems to negatively affect BPV and the association of treatment negatively influences HRV.

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Physical Training as a Blood Pressure Reducer and a Remodeler of Cardiac Fibers in Spontaneously Hypertensive Rats (SHR)

Cardiology and Angiology An International Journal ◽

10.9734/ca/2021/v10i430175 ◽

2021 ◽

pp. 22-30

Author(s):

Mariana Molinar Mauad Cintra ◽

Matheus Ribeiro Bizuti ◽

Octávio Barbosa Neto ◽

Marlene Antônia dos Reis ◽

Lenaldo Branco Rocha ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Physical Training ◽

Spontaneously Hypertensive Rats ◽

Cardiac Fibrosis ◽

Left Ventricular ◽

Type Iii Collagen ◽

Hypertensive Rats ◽

Spontaneously Hypertensive ◽

Type Iii

Background: Hypertension is the most prevalent of all cardiovascular diseases, reaching target organs such as the heart. Blood pressure control is critical for preventing organ damage induced by hypertension. Objective: To analyze blood pressure, heart rate, left ventricular thickness, the percentage of cardiac fibrosis and the percentage of type III collagen in Spontaneously Hypertensive Rats (SHR) submitted to swimming physical training. Methods: The experimental groups were composed of male Wistar Kyoto (WKY) rats (309-311g), which were divided into: 1) Normotensive Sedentary group (SN) (n = 6); 2) Trained Normotensive group (TN) (n = 6); 3) Sedentary Hypertensive group (SH) (n = 6); 4) Trained Hypertensive group (TH) (n = 6). After the end of the protocol, the animals were initially anesthetized to measure blood pressure. Results: Physical training was responsible for decreasing blood pressure (F = 16,968; p <0.001) and heart rate (F = 10.710; p = 0.004) in the trained groups (normotensive and hypertensive). Moreover, training was responsible for providing an increase in the thickness of the left ventricle (F = 7,254; p = 0.014) and a reduction in the percentage of cardiac fibrosis (F = 16,081; p <0.001). Furthermore, it was observed that the trained group had lower values of type III collagen (F = 13,166; p = 0.002). Conclusions: Physical swimming training triggered a decrease in blood pressure, heart rate, the percentage of fibrosis and the percentage of type III collagen. In addition, there was also a cardiac remodeling due to the increase in left ventricular hypertrophy.

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Relationship Between Arterial Distensibility and Low-Frequency Power Spectrum of Blood Pressure in Spontaneously Hypertensive Rats

Journal of Cardiovascular Pharmacology ◽

10.1097/00005344-200201000-00011 ◽

2002 ◽

Vol 39 (1) ◽

pp. 98-106 ◽

Cited By ~ 18

Author(s):

Hubert Dabiré ◽

Patrick Lacolley ◽

Kamel Chaouche-Teyara ◽

Berthe Fournier ◽

Michel E. Safar

Keyword(s):

Blood Pressure ◽

Power Spectrum ◽

Spontaneously Hypertensive Rats ◽

Low Frequency ◽

Hypertensive Rats ◽

Arterial Distensibility ◽

Spontaneously Hypertensive ◽

Low Frequency Power ◽

Frequency Power Spectrum ◽

Frequency Power

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Regression of myocardial hypertrophy and influence of adrenergic system

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1983.244.1.h97 ◽

1983 ◽

Vol 244 (1) ◽

pp. H97-H101 ◽

Cited By ~ 4

Author(s):

S. Sen ◽

R. C. Tarazi

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Regression Analysis ◽

Arterial Pressure ◽

Spontaneously Hypertensive Rats ◽

Myocardial Hypertrophy ◽

Cardiac Response ◽

Adrenergic System ◽

Hypertensive Rats ◽

Spontaneously Hypertensive

Studies of regression of myocardial hypertrophy in spontaneously hypertensive rats (SHR) suggest that the adrenergic system may play an important role in the reversal of hypertrophy. The effect of propranolol on reversal of hypertrophy, however, is still controversial. This study describes the effect of propranolol, given alone or in combination with hydralazine in different ratios for 4 wk, on blood pressure (BP), ventricular weight, and myocardial catecholamine (MC) concentrations. The data show that a certain ratio of propranolol to hydralazine (750:30) leads to moderate BP control (196-156 mmHg) without increased MC (634 vs. 552 ng/g) and moderately reduced hypertrophy. Reduction of BP alone with increased MC (hydralazine alone) or reduction of MC without BP control (propranolol alone) failed to reduce hypertrophy. A significant correlation between both ventricular weight and heart rate with MC (r = 0.6) was obtained by multiple regression analysis. This study suggests that adrenergic factors seem to play an important role in modulating structural cardiac response to variations in arterial pressure.

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