McPhail L T, Jones D R
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada.
Physiol Biochem Zool. 1999 Mar-Apr;72(2):164-9. doi: 10.1086/316662.
Autonomic nervous control of heart rate was studied in voluntarily diving ducks (Aythya affinis). Ducks were injected with the muscarinic blocker atropine, the beta-adrenergic blocker nadolol, the beta-adrenergic agonist isoproterenol, and a combination of both atropine and nadolol. Saline injection was used as a control treatment. The reduction in heart rate (from the predive level) normally seen during a dive was abolished by atropine. Nadolol reduced heart rate during all phases of diving activity-predive, dive, and postdive-indicating that sympathetic output to the heart was not withdrawn during diving. Isoproterenol increased heart rate before, during, and after the dive, although the proportional increase in heart rate was not as high during the dive as compared with the increase in routine heart rate or heart rate during the predive or postdive phase. The parasympathetic system predominates in the control of heart rate during diving despite the maintenance of efferent sympathetic influences to the heart, perhaps due to accentuated antagonism between the two branches of the autonomic nervous system.
对自愿潜水的鸭子（美洲黑鸭）的心率自主神经控制进行了研究。给鸭子注射了毒蕈碱阻滞剂阿托品、β-肾上腺素能阻滞剂纳多洛尔、β-肾上腺素能激动剂异丙肾上腺素以及阿托品和纳多洛尔的组合。注射生理盐水作为对照处理。潜水时通常出现的心率降低（相对于潜水前水平）被阿托品消除。纳多洛尔在潜水活动的所有阶段——潜水前、潜水期间和潜水后——均降低了心率，这表明潜水时心脏的交感神经输出并未撤回。异丙肾上腺素在潜水前、潜水期间和潜水后均使心率增加，尽管与常规心率增加或潜水前或潜水后阶段的心率增加相比，潜水期间心率的成比例增加没有那么高。尽管对心脏维持着传出性交感神经影响，但在潜水期间副交感神经系统在心率控制中占主导地位，这可能是由于自主神经系统的两个分支之间的拮抗作用加剧所致。
