Exercise-induced neuroplasticity in autonomic nuclei restores the cardiac vagal tone and baroreflex dysfunction in aged hypertensive rats

Author(s)

Dellacqua, Lais Oliveira ; Gomes, Paula Magalhaes ; Batista, Julia Santos ; Michelini, Lisete Compagno ; Antunes, Vagner Roberto

• Document type: Journal article
• Source: Journal of Applied Physiology; v. 136, n. 1, p. 10-pg., 2024-01-07.

Abstract

Aging is accompanied by considerable deterioration of homeostatic systems, such as autonomic imbalance characterized by heightened sympathetic activity, lower parasympathetic tone, and depressed heart rate (HR) variability, which are aggravated by hypertension. Here, we hypothesized that these age-related deficits in aged hypertensive rats can be ameliorated by exercise training, with benefits to the cardiovascular system. Therefore, male 22-mo-old spontaneously hypertensive rats (SHRs) and age-matched Wistar Kyoto (WKY) submitted to moderate-intensity exercise training (T) or kept sedentary (S) for 8 wk were evaluated for hemodynamic/autonomic parameters, baroreflex sensitivity, cardiac sympathetic/parasympathetic tone and analysis of dopamine beta-hydroxylase (DBH+) and oxytocin (OT+) pathways of autonomic brain nuclei. Aged SHR-S versus WKY-S exhibited elevated mean arterial pressure (MAP: +51%) and HR (+20%), augmented pressure/HR variability, no cardiac vagal tone, and depressed reflex control of the heart (HR range, -28%; gain, -49%). SHR-T exhibited a lower resting HR, a partial reduction in the MAP (-14%), in the pressure/HR variabilities, and restored parasympathetic modulation, with improvement of baroreceptor reflex control when compared with SHR-S. Exercise training increased the ascending DBH+ projections conveying peripheral information to the paraventricular nucleus of hypothalamus (PVN), augmented the expression of OT+ neurons, and reduced the density of DBH+ neurons in the rostral ventrolateral medulla (RVLM) of SHR-T. Data indicate that exercise training induces beneficial neuroplasticity in brain autonomic circuitry, and it is highly effective to restore the parasympathetic tone, and attenuation of age-related autonomic imbalance and baroreflex dysfunction, thus conferring long-term benefits for cardiovascular control in aged hypertensive individuals. (AU)

• FAPESP's process: 12/22368-7 - Evaluation of transcription factors of the hypothalamic-brainstem nuclei and cardiovascular benefits of exercising training in aging SHR
• Grantee: Laís Oliveira Dellacqua
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 22/07465-8 - The role of microglia in modulating the deleterious effects of hypertension on Blood-Brain Barrier (BBB) permeability: the benefits of the aerobic exercise training
• Grantee: Paula Magalhães Gomes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/06206-0 - Gene expression changes of neuropeptides and proinflammatory factors of the hypothalamus and brainstem nucleus involved with cardiovascular regulation in diet-induced obesity animals
• Grantee: Vagner Roberto Antunes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/14544-6 - Blood-brain barrier: a new paradigm in the treatment of hypertension
• Grantee: Lisete Compagno Michelini
• Support Opportunities: Research Projects - Thematic Grants
• 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 Opportunities: Research Projects - Thematic Grants