Swimming training reduces iNOS expression, augments the antioxidant defense and reduces sympathetic responsiveness in the rostral ventrolateral medulla of normotensive male rats

Author(s)

Raquel, Hiviny de Ataides ^{[1, 2]} ; Souza Guazelli, Carla Fabiana ^[3] ; Verri Jr, Waldiceu A. ; Michelini, Lisete C. ^[1] ; Martins-Pinge, Marli Cardoso ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, Sao Paulo, SP - Brazil

^[2] Univ Estadual Londrina, Ctr Biol Sci, Dept Physiol Sci, Rodovia Celso Garcia Cid, Km 380, Campus Univ, BR-86055900 Londrina, Parana - Brazil

^[3] Univ Estadual Londrina, Ctr Biol Sci, Dept Pathol Sci, Londrina, Parana - Brazil

• Document type: Journal article
• Source: Brain Research Bulletin; v. 170, p. 225-233, MAY 2021.
• Web of Science Citations: 0

Abstract

We sought to investigate whether RVLM iNOS activity and oxidative profile may participate in the reduction of sympathetic responsiveness in swimming trained normotensive rats. Sedentary (S) and swimming trained (T) Wistar male rats chronically instrumented with an arterial catheter and guide cannula into the RVLM were submitted to continuous pressure and heart rate (HR) recordings and determination of autonomic control (power spectral analysis) before and after unilateral RVLM iNOS inhibition (aminoguanidine, 250 pmol/100 nL). Other S and T rats received local L-glutamate micminjection (5 nmol/100 nL). In separate S and T groups not submitted to brainstem cannulation, fresh bilateral RVLM punchs were collected for iNOS gene expression (qPCR); reduced glutathione and lipid pemxidation quantification (spectrophotometry); iron-reducing antioxidant (FRAP) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS(+)) scavenger assays. iNOS gene expression was confirmed in fixed RVLM slices (immunofluorescence). T rats exhibited resting bradycardia, lower sympathovagal balance, reduced RVLM iNOS gene/protein expression and higher antioxidant capacity. Decreased iNOS expression was positively correlated with reduced HR. Pressor and tachycardic response to L-Glutamate were smaller in T rats. Aminoguanidine micminjection reduced sympathetic activity in S rats but did not change it in T rats expressing reduced RVLM iNOS content. Our data indicate that iNOS, expressed in the RVLM of normotensive male rats, has tonic effects on sympathetic activity and that swimming training is an efficient tool to reduce iNOS expression and augment the antioxidant defense, thus reducing glutamatergic responsiveness and sympathetic drive to cardiovascular effectors. (AU)

• FAPESP's process: 15/24935-4 - BLOOD-BRAIN BARRIER AND AUTONOMIC REGULATION IN HYPERTENSION: EFFECTS OF ANGIOTENSIN II AND AEROBIC TRAINING
• Grantee: Lisete Compagno Michelini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/22156-3 - Effects of heart failure and aerobic training on blood-brain barrier integrity in autonomic brain areas: Mechanisms conditioning the paracellular and transcellular transport.
• Grantee: Hiviny de Ataides Raquel
• Support Opportunities: Scholarships in Brazil - Post-Doctoral