Efeitos do exercício físico sobre o controle autonômico e função vascular de ratos expostos aos compostos nocivos do tabaco

• Ano de defesa: 2019
• Autor(a) principal: Nunez, Ivan Alfredo Rodriguez [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Exercise; Nicotine; Autonomic Nervous System; Barorreflex Sensitive; Exercício; Nicotina; Sistema Nervoso Autonomo; Sensibilidade Barorreflexa
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=7943636; https://repositorio.unifesp.br/handle/11600/60070

Introduction: Smoking is an important risk factor for the development of cardiovascular disease (CVD). In turn, nicotine has been shown to induce oxidative stress and endothelial dysfunction in blood vessels. However, its effects on autonomic control have been scarcely studied. On the other hand, physical exercise (PE) is an effective therapeutic approach for the treatment of CVD. However, there are few studies evaluating the effect of PE on smoking-induced damage and the effects on autonomic control have not been determined. The aim of this study was to evaluate the effects of EF on the control of cardiovascular autonomic balance and endothelial function of nicotine-treated rats. Methodology: In the first chapter Wistar rats were divided into 4 groups: Control, Control + PE, Nicotine and Nicotine + PE. The PE protocol was characterized by 45 minutes of moderate treadmill training at an intensity of 60 - 70% of maximum speed 5 times a week for 4 consecutive weeks. Nicotine was administered for 28 days subcutaneously at a dose of 1 mg / kg. 24 hours after the experimental protocols, the animals were anesthetized and catheterized to record heart rate (HR), blood pressure (BP) and heart rate variability (HRV). Baroreflex sensitivity (BRS) for HR control was determined. Additionally, basal and maximal renal sympathetic activity (rSNA) was determined, as well as the BRS for rSNA control. In the second chapter, the properties of the sympathetic neurovascular transmission of the Control, Nicotine and Nicotine + EF groups were determined in an isolated vas deferens (CD) preparation. Additionally, the effect of cigarette smoke exposure on vascular reactivity of Sprague Dawley rats distributed into three groups: Control, Tobacco and Tobacco + EF was evaluated. Results: In the first chapter the animals of the Nicotine group presented a lower HRV, BRS and baseline rSNA. On the other hand, EF was effective in preventing changes in HRV, BRS and rSNA. In the second chapter, chronic nicotine treatment decreased the acute potentiation of neurogenic and myogenic contractions induced by nicotinic receptor activation, which was not prevented by PE. However, PE reversed endothelial dysfunction induced by exposure to tobacco smoke. Conclusion: Nicotine treatment altered the autonomic control of the cardiovascular system through baroreceptor reflex inhibition, decreased HRV and basal rSNA; which was prevented by the PE. However, at the level of the neurovascular junction PE exerts the positive effects mainly at the endothelial level.