Exercise training preserves vagal preganglionic neurones and restores parasympathetic tonus in heart failure

Author(s)

Ichige, Marcelo H. A. ; Santos, Carla R. ; Jordao, Camila P. ; Ceroni, Alexandre ; Negrao, Carlos E. ; Michelini, Lisete C.

• Document type: Journal article
• Source: JOURNAL OF PHYSIOLOGY-LONDON; v. 594, n. 21, p. 6241-6254, NOV 2016.
• Web of Science Citations: 10

Abstract

Exercise training is an efficient tool to attenuate sympathoexcitation, a hallmark of heart failure (HF). Although sympathetic modulation in HF is widely studied, information regarding parasympathetic control is lacking. We examined the combined effects of sympathetic and vagal tonus to the heart in sedentary (Sed) and exercise trained (ET) HF rats and the contribution of respective premotor and preganglionic neurones. Wistar rats submitted to coronary artery ligation or sham surgery were assigned to training or sedentary protocols for 6weeks. After haemodynamic, autonomic tonus (atropine and atenolol i.v.) and ventricular function determinations, brains were collected for immunoreactivity assays (choline acetyltransferase, ChATir; dopamine -hydroxylase, DBHir) and neuronal counting in the dorsal motor nucleus of vagus (DMV), nucleus ambiguus (NA) and rostroventrolateral medulla (RVLM). HF-Sed vs. SHAM-Sed exhibited decreased exercise capacity, reduced ejection fraction, increased left ventricle end diastolic pressure, smaller positive and negative dP/dt, decreased intrinsic heart rate (IHR), lower parasympathetic and higher sympathetic tonus, reduced preganglionic vagal neurones and ChATir in the DMV/NA, and increased RVLM DBHir. Training increased treadmill performance, normalized autonomic tonus and IHR, restored the number of DMV and NA neurones and corrected ChATir without affecting ventricular function. There were strong positive correlations between parasympathetic tonus and ChATir in NA and DMV. RVLM DBHir was also normalized by training, but there was no change in neurone number and no correlation with sympathetic tonus. Training-induced preservation of preganglionic vagal neurones is crucial to normalize parasympathetic activity and restore autonomic balance to the heart even in the persistence of cardiac dysfunction. (AU)

• FAPESP's process: 14/06772-8 - Heart Failure and Exercise Training: Effects to the Cardiac Autonomic Nervous System
• Grantee: Marcelo Hiro Akiyoshi Ichige
• Support type: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 11/51410-9 - Amelioration of the autonomic imbalances of old age with exercise: exploring the molecular and physiological mechanisms
• Grantee: Lisete Compagno Michelini
• Support type: Research Projects - Thematic Grants