The physiology of the alligator heart: left aortic flow patterns and right-to-left shunts
The physiology of the alligator heart: left aortic flow patterns and right-to-left shunts
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鳄鱼心脏的生理学：左主动脉血流模式和从右到左的分流
DOI：
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
G. Shelton
中科院分区：
文献类型：
--
作者：
D. Jones;G. Shelton
麻醉和清醒状态下的鳄鱼心脏中的血压以及主动脉弓中的压力和流量都被记录下来。与麻醉动物相比，清醒时的全身血压显著降低[5.22+/−0.57kPa(N=3)比9.85+/−0.46kPa(N=5)]，心输出量增加[51.6+/−3.5mlmin-1 kg-1(N=3)比25.5+/−8.2mlmin-1 kg-1(N=5)]。利用药物干预，可以在所有扬子鳄体内诱导两种类型的从右向左的分流。其中一例是在向循环右侧注入乙酰胆碱(ACh)后建立的，左主动脉血流是一种顺行单相脉搏，当肺动脉压超过全身血压时发生。因此，这种左主动脉血流模式也可以通过机械阻断双肺动脉来诱导。在分流期间，大约四分之一的心输出量可以绕过肺。然而，这种左主动脉血流模式在药物干预以外的任何情况下都从未见过。在另一种类型的分流中，左主动脉血流呈双相，开始于收缩时，随着右室前向血流的开始而逐渐缩短，这种分流是由左循环左侧注射ACh引起的。这种分流的建立依赖于体压的大小和关闭肺流出道后右室收缩产生的压力。在分流术中，肺旁路出血量很少(13.7+/−，心输出量的5%)，但最大可能是心输出量的25%。这种分流是在静息动物体内自然发生的，可以维持相当长的时间(13.2分钟)。目前的观察证实了先前在麻醉鳄鱼上所做的工作，并通过显示两种可能的分流类型来扩展先前的工作。最后，我们认为鳄鱼从右向左的血液分流可能与摄食后发生的碱性潮汐有关，因此鳄鱼中枢心血管系统的独特设计可能与胃肠道和心肺生理学有关。
Blood pressures have been recorded in the heart along with pressures and flow in the aortic arches of anaesthetized and awake alligators. Systemic blood pressures were significantly lower [5.22+/−0.57 kPa (N=3) versus 9.85+/−0.46 kPa (N=5)] and cardiac outputs higher [51.6+/−3.5 ml min-1 kg-1 (N=3) versus 25.5+/−8.2 ml min-1 kg-1 (N=5)] in awake compared with anaesthetized animals. Using pharmacological interventions, two types of right-to-left shunt could be induced in all alligators. In one, established after acetylcholine (ACh) injection into the right side of the circulation, left aortic flow was an anterograde monophasic pulse which occurred when pulmonary pressure exceeded systemic blood pressure. Hence, this left aortic flow pattern could also be induced by mechanical occlusion of both pulmonary arteries. About one-quarter of cardiac output could bypass the lungs during this shunt. However, this left aortic flow pattern was never seen under any conditions other than pharmacological intervention. In the other type of shunt, induced pharmacologically by ACh injection into the left side of the circulation, left aortic flow was biphasic with a period of backflow, initiated during systole, being progressively shortened by the onset of forward flow from the right ventricle. Establishment of this type of shunt depended on the magnitude of both the systemic pressure and the pressure generated by right ventricular contraction after closure of the pulmonary outflow tract. The amount of blood bypassing the lungs during this shunt was small (13.7+/−5 % of cardiac output) but, at maximum, could be almost 25 % of cardiac output. This shunt occurred naturally in resting animals and could be maintained for substantial periods (13.2 min). The present observations confirm those made previously on anaesthetized alligators and extend previous work by showing two potential types of shunt. Finally, we suggest that right-to-left blood shunting in crocodilians may be related to the ‘alkaline tide’ that occurs after feeding, so the unique design of the central cardiovascular system in crocodilians could relate to both gastrointestinal and cardiorespiratory physiology.
鳄鱼血液中的氧结合与温度、潜水和“碱潮”有关。
DOI：
10.1152/ajpregu.1986.251.5.r901
发表时间：
1986
期刊：
The American journal of physiology
影响因子：
--
作者：
Weber,RE;White,FN
通讯作者：
White,FN