Departamento de Fisiologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
Departamento de Kinesiología, Facultad de Medicina, Universidad de Concepción, Chile.
Can J Physiol Pharmacol. 2021 Aug;99(8):786-794. doi: 10.1139/cjpp-2020-0381. Epub 2020 Dec 8.
Chronic nicotine exposure may increase cardiovascular risk by impairing the cardiac autonomic function. Besides, physical exercise (PE) has shown to improve cardiovascular health. Thus, we aimed to investigate the effects of PE on baroreflex sensitivity (BRS), heart rate variability (HRV), and sympathetic nerve activity (SNA) in chronically nicotine-exposed rats. Male Wistar rats were assigned to four independent groups: Control (treated with saline solution), Control+Ex (treated with saline and submitted to treadmill training), Nicotine (treated with Nicotine), and Nicotine+Ex (treated with nicotine and submitted to treadmill training). Nicotine (1 mg·kg) was administered daily for 28 consecutive days. PE consisted of running exercise (60%-70% of maximal aerobic capacity) for 45 min, 5 days per week, for 4 weeks. At the end of the protocol, cardiac BRS, HRV, renal SNA (rSNA), and renal BRS were assessed. Nicotine treatment decreased absolute values of HRV indexes, increased low frequency/high frequency ratio of HRV, reduced the bradycardic and sympatho-inhibitory baroreceptor reflex responses, and reduced the rSNA. PE effectively restored time-domain HRV indexes, the bradycardic and sympatho-inhibitory reflex responses, and the rSNA in chronic nicotine-treated rats. PE was effective in preventing the deterioration of time-domain parameters of HRV, arterial baroreceptor dysfunction, and the rSNA after nicotine treatment.
慢性尼古丁暴露可能通过损害心脏自主功能增加心血管风险。此外，体育锻炼（PE）已被证明可以改善心血管健康。因此，我们旨在研究 PE 对慢性尼古丁暴露大鼠的血压反射敏感性（BRS）、心率变异性（HRV）和交感神经活性（SNA）的影响。雄性 Wistar 大鼠被分为四个独立的组：对照组（给予生理盐水）、对照组+运动组（给予生理盐水并进行跑步机训练）、尼古丁组（给予尼古丁）和尼古丁+运动组（给予尼古丁并进行跑步机训练）。尼古丁（1mg·kg）每天给药，连续 28 天。PE 包括 45 分钟的跑步运动（最大有氧能力的 60%-70%），每周 5 天，持续 4 周。在方案结束时，评估心脏 BRS、HRV、肾 SNA（rSNA）和肾 BRS。尼古丁处理降低了 HRV 指标的绝对值，增加了 HRV 的低频/高频比值，降低了心动过缓和交感神经抑制性压力感受器反射反应，并降低了 rSNA。PE 有效地恢复了慢性尼古丁处理大鼠的 HRV 时间域指标、心动过缓和交感神经抑制性反射反应以及 rSNA。PE 有效预防了尼古丁处理后 HRV 的时间域参数、动脉压力感受器功能障碍和 rSNA 的恶化。
