Butler P J, Woakes A J
J Appl Physiol Respir Environ Exerc Physiol. 1982 Dec;53(6):1405-10. doi: 10.1152/jappl.1982.53.6.1405.
Previous work has shown that during forcible submersion of domestic ducks there is a gradual reduction in heart rate to 10-20% of its predive value after 45-60 s. Bilateral denervation of the carotid body chemoreceptors abolishes most of this bradycardia. By use of implanted radio transmitters it has been shown that in free-swimming tufted ducks, Aythya fuligula, there is an immediate reduction in heart rate, on spontaneous diving, from an elevated predive level. It then increases for a few seconds before it stabilizes at a level similar to that recorded when the duck is swimming fairly vigorously. The present study has shown that, following bilateral denervation of the carotid bodies, there is a significant increase in mean dive duration but no effect on the immediate reduction in heart rate on submersion. Heart rate is, however, significantly higher toward the end of spontaneous dives after carotid body denervation. Unlike the situation in mallards and their domesticated varieties, carotid body denervation has no effect on heart rate in tufted ducks during the first 40 s of forced dives. The carotid bodies therefore do not play the dominant role in cardiac control during submersion of diving ducks that has been suggested by work involving the forcible submersion of the mallard duck and its domesticated varieties.
先前的研究表明，家鸭在被迫浸水时，心率会逐渐降低，45 - 60秒后降至潜水前值的10 - 20%。双侧切除颈动脉体化学感受器可消除大部分这种心动过缓。通过使用植入式无线电发射器已表明，在自由游动的凤头潜鸭（Aythya fuligula）中，自发潜水时，心率会从升高的潜水前水平立即降低。然后在稳定在与鸭子剧烈游动时记录的水平相似之前，心率会升高几秒钟。本研究表明，双侧切除颈动脉体后，平均潜水持续时间显著增加，但对浸水时心率的立即降低没有影响。然而，颈动脉体去神经支配后，自发潜水接近尾声时心率显著更高。与绿头鸭及其驯化品种的情况不同，双侧切除颈动脉体对凤头潜鸭在强制潜水的前40秒内心率没有影响。因此，在涉及绿头鸭及其驯化品种被迫浸水的研究中所表明的那样，颈动脉体在潜水鸭浸水期间的心脏控制中并不起主导作用。
