Apte C V, Dikshit M B, Prasad B A
Department of Physiology, Armed Forces Medical College, Pune.
Indian J Physiol Pharmacol. 1992 Jul;36(3):149-54.
Ten healthy males (age 34 +/- 3 yr 9 SE) underwent 40 min of heat exposure (WD 39.7.C) after 2 hours of ingesting 120 mg of Propranolol (Inderal; ICI), or a placebo, in a random manner, the exposures being about a week apart. That there was no placebo effect was ensured by giving a control run (no medication). In the placebo trials, the end-experiment heart rate had increased by 52%, while after propranolol the increase was only 43%. Regression analysis showed that with the placebo, the HR increased by 22 beats/min/o rise in core (aural) temperature, while with propranolol, the rise (14 beats/min) was significantly lower (P < 0.02). The various heat strain indices viz the Craig's Index, the Body heat storage (Kilocals/m2/hr), and the effective heat storage were also similar for both the treatments. We conclude that beta-adrenoreceptor activity plays a significant role in producing tachycardia of heat exposure in humans, but blocking this activity with propranolol does not affect tolerance to heat stress.
10名健康男性（年龄34±3岁，标准误9）在随机服用120毫克普萘洛尔（心得安；帝国化学工业公司）或安慰剂2小时后，接受了40分钟的热暴露（湿球温度39.7℃），两次暴露间隔约一周。通过进行一次对照试验（不服用药物）确保不存在安慰剂效应。在安慰剂试验中，实验结束时心率增加了52%，而服用普萘洛尔后心率仅增加43%。回归分析表明，服用安慰剂时，心率随核心（耳部）温度每升高1℃增加22次/分钟，而服用普萘洛尔时，心率升高幅度（14次/分钟）显著更低（P<0.02）。两种治疗的各种热应激指标，即克雷格指数、身体蓄热量（千卡/平方米/小时）和有效蓄热量也相似。我们得出结论，β-肾上腺素能受体活性在人类热暴露引起的心动过速中起重要作用，但用普萘洛尔阻断该活性并不影响对热应激的耐受性。
