Aerial Respiration in the Banded Knife Fish Gymnotus carapo (Teleostei: Gymnotoidei)
Aerial Respiration in the Banded Knife Fish Gymnotus carapo (Teleostei: Gymnotoidei)
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带状刀鱼 Gymnotus carapo（Teleostei：Gymnotoidei）的空中呼吸
DOI：
10.1086/physzool.57.1.30155979
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
W. Fink
中科院分区：
文献类型：
--
作者：
K. Liem;B. Eclancher;W. Fink
这一解剖和实验研究表明，带状刀鱼Gymnotus carapo能够通过高度特化的、扩大的和血运丰富的气囊后腔呼吸空气。空气通风是通过一个独特的专门的食管力泵的动作来完成的。电影放射线摄影显示，空气通风是以一致的顺序进行的，吸气之后是两次或两次以上的呼气。据推测，之前的吸入暂时提高了气囊内的压力，作为通过相对较窄和较长的气动管道通过静水压力被动呼气的初步步骤。在29-31℃的温度下，当在空气平衡的水中，在空气的47%，72%和95%的条件下，裸藻分别从空气中提取1.63，1.12和0.76mmolO₂h⁻？kg⁻？(Ṁ)。从水中提取的氧量(ṀWO2)分别为0.5 6、1.0 3和1.33mmolO₂h⁻？kg⁻？水中95%~47%常氧的总ṀO2为2.23±0.17mmolO₂h⁻？kg⁻？当水的PO2高于200托时，鱼可以依靠水呼吸，但当PO2低于60托时，它依赖空气。当无法接触到空气时，它能够在29℃的温度下将其总的O₂消耗量降低到对照₂的69%。水中的O₂水平越高，温度越低，当空气接触受到阻碍或禁止时，水生呼吸就会增加，而在相反的条件下，空气呼吸就会增加。
This anatomical and experimental study has revealed that the banded knife fish Gymnotus carapo is capable of air breathing by means of the highly specialized, enlarged, and vascularized posterior chamber of the gas bladder. Air ventilation is accomplished by the action of a uniquely specialized esophageal force pump. Cineradiography has shown that air ventilation proceeds in a consistent sequence, with an inhalation followed by two or more exhalations. It is postulated that prior inhalation raises the pressure within the gas bladder temporarily as a preliminary step to passive exhalation of air by hydrostatic pressure via a relatively narrow and long pneumatic duct. At temperatures of 29-31 C Gymnotus extracts 1.63, 1.12, and 0.76 mmol O₂ h⁻¹ kg⁻¹ from air (Ṁao2) when it is in air-equilibrated water at 47%, 72%, and 95%, respectively, of air at STP. The amounts of oxygen extracted from water (Ṁwo2) are, respectively, 0.56, 1.03, and 1.33 mmol O₂ h⁻¹ kg⁻¹. Total Ṁo2 between 95% and 47% normoxia in water is 2.23 ± 0.17 mmol O₂ h⁻¹ kg⁻¹. When Po2 of water is higher than 200 torr the fish can rely on water breathing, but when Po2 is below 60 torr it relies on air. When Gymnotus has no access to air, it is able to lower its total O₂ consumption to 69% of the control Mo2 at a temperature of 29 C. Aquatic respiration increases with higher O₂ levels in water, lower temperatures, and when access to air is either hindered or prohibited, while aerial respiration increases under the opposite conditions.