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Nitric Oxide Participation in Thermoregulatory Adjustments During Physical Exercise in Spontaneously Hypertensive Rats
Author(s) -
Drummond Lucas Rios,
Campos Helton Oliveira,
Pires Washington,
Andrade Lima Paulo Marcelo,
Horta Nayara Abreu Coelho,
PrímolaGomes Thales Nicolau,
Coimbra Cândido Celso
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1085.5
Subject(s) - sodium nitroprusside , medicine , nitric oxide , ventricle , heart rate , endocrinology , anesthesia , blood pressure
This study aimed to investigate the nitric oxide participation in thermoregulatory adjustments during physical exercise in spontaneously hypertensive rats. All experimental procedures were approved by the Ethics Committee on Animal Use at Universidade Federal de Minas Gerais (# 21/2015). Eight male Wistar rats (SAP = 119 ± 3 mmHg) and spontaneously hypertensive rats (SHR; SAP = 195 ± 7 mmHg) with 16 weeks of age were used in the experiments. The rats received an implant of a chronic guide cannula in the lateral cerebral ventricle and a temperature sensor into the abdominal cavity. After recovery, the animals were familiarized to run on a treadmill, and then, each animal was subjected to two constant‐speed exercise protocols at 60% of maximal speed attained in the incremental exercise until fatigue. On the day of the experiments, the rats were assigned to receive a 2 μL intracerebroventricular injection of either NaCl (0.15 mol/L) or sodium nitroprusside (SNP; 8.4 mmol) setting four groups, Wistar SAL, Wistar SNP, SHR SAL and SHR SNP. The tail skin temperature (T skin ) and abdominal temperature (T abd ) were recorded every minute throughout the exercise trials. The T skin and T abd dynamics were evaluated by the temperature variation (temperature in each minute ‐ the initial temperature). In Wistar groups, the SNP group showed a greater increase in T skin from the 14 th min until the fatigue (3.12 ± 0.33°C vs. 1.60 ± 0.47°C, fatigue; p < 0.05) with the lower increase in T abd when compared with SAL group from the 18 th min until the fatigue (1.28 ± 0.16°C vs. 1.71 ± 0.26°C; fatigue, p < 0.05). In SHR groups, the SNP group showed a greater increase in T skin from the 8 th until the 19 th min (1.58 ± 0.83°C vs. −0.40 ± 0.88°C, 15 th min; p < 0.05) and lower increase in T abd when compared with SAL group from the 23 th min until the fatigue (1.09 ± 0.13°C vs. 1.70 ± 0.18°C; fatigue, p < 0.05). SHR groups performed a decreased workload during exercise (SAL: 200.1 ± 23.2 J vs. 277.0 ± 27.1 J, p < 0.05; SNP: 206.0 ± 23.2 J vs. 299.0 ± 27.1 J, p < 0.05) when compared with Wistar groups. The SNP injection did not modify the workload performed during the exercise in Wistar and SHR groups ( p > 0.05). We conclude that central injection of sodium nitroprusside increased heat dissipation, resulting in a lower increase in abdominal temperature during exercise in Wistar and SHR rats, without modify physical performance. Support or Funding Information Financial Support: FAPEMIG, CAPES and CNPq.