Exercise training improves chemoreflex disfunction in diabetic rats

Abstract

The aim of the present study was to investigate the effects of exercise training on arterial pressure, heart rate and chemoreflex sensitivity in STZ-induced diabetic rats. The animals were divided into three groups: control (SC, n = 6), sedentary diabetic (SD, n = 6) and trained diabetic (TD, n = 6). After 1 week of diabetes induction (Streptozotocin, 50 mg/kg, iv), male Wistar rats were submitted to exercise training for 10 weeks on a treadmill. Arterial pressure signals were obtained and processed with a data acquisition system (CODAS, 1 KHz). Potassium cyanide (KCN, 100ug/kg) was used to evaluated bradycardic response evoked by chemoreflex activation. Diabetes bradycardia and hypotension (SD: 274 ± 6 bpm and 94 ± 2 mmHg vs SC: 332 ± 5bpm and 108 ± 2 mmHg) were attenuated by training (TD: 299 ± 5 bpm and 107 ± 2 mmHg). Bradycardic response was decreased in SD rats (33 ± 5 bpm) when compared to SC rats (182 ± 3 bpm) and TD rats (89 ± 10 bpm). In conclusion, exercise training reversed hypotension and bradycardia and improved chemreflex sensitivity in STZ-diabetic rats. Considering that diabetics with abnormal cardiovascular reflexes show higher mortality than diabetics with normal autonomic reflex function, the results obtained suggest that exercise training may contribute to the reduction in cardiovascular risk in this population and must be considered in the management of diabetic patients