STUDY OF CHRONIC CHOLINERGIC STIMULATION ASSOCIATED WITH AEROBIC PHYSICAL TRAINING ON CARDIAC FUNCTIONALITY AND CONTRACTILITY IN HYPERTENSIVE RATS

• Grant number: 23/13514-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): December 01, 2023
• Effective date (End): November 30, 2024
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Hugo Celso Dutra de Souza
• Grantee: Maria Eduarda Dilarri
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

INTRODUCTION: Cholinergic stimulation through pharmacological inhibition of acetylcholinesterase produces effects on cardiac autonomic control that resemble those obtained through aerobic physical training, both in humans and experimental models. These effects are mainly characterized by a significant increase in parasympathetic (vagal) autonomic component influence on the heart, evidenced by increased vagal tone, heart rate variability (HRV), and baroreflex sensitivity (BRS). However, so far, no study has addressed the consequences of chronic cholinergic stimulation on ventricular contractility associated with coronary bed reactivity. Furthermore, as the autonomic adaptations induced by physical training resemble those obtained through chronic cholinergic stimulation, the combination of these two treatments may result in greater morphofunctional benefits. OBJECTIVE: To investigate the effects of treatment with an acetylcholinesterase inhibitor (pyridostigmine bromide; 15mg/kg) in spontaneously hypertensive rats (SHR) on parameters of ventricular contractility and coronary bed reactivity, and to evaluate the effects of the combination of cholinergic stimulation with aerobic physical training on the investigated parameters. METHODS: SHR rats (N=32) will be divided into two main groups: trained (N=16) and untrained (N=16). Each main group will be subdivided into two smaller groups (N=8); treated with pyridostigmine bromide (15mg/kg/day) for 02 weeks and treated with vehicle (H2O). All groups will undergo the following protocols: plethysmographic evaluation of blood pressure; and evaluation of coronary pharmacological reactivity and cardiac contractility using the Langendorff technique.