Sakuragui M M, Sanches J R, Fernandes M N
Department of Physiological Sciences, Federal University of São Carlos, C. Postal 676, 13565-905 São Carlos, SP, Brazil.
J Comp Physiol B. 2003 Jun;173(4):309-17. doi: 10.1007/s00360-003-0337-9. Epub 2003 Apr 2.
The effect of chloride cell proliferation on the respiratory function was evaluated by measuring oxygen consumption (VO2) and ventilatory parameters during normoxia and gradual hypoxia in the tropical fish Hoplias malabaricus. Chloride cell proliferation was induced by keeping fish in deionized water, and the effect on the respiratory function was measured on the 1st, 2nd, and 7th day in this water using a flow-through respirometry system. Plasma osmolarity and the partial pressure of arterial oxygen (PaO2) and carbon dioxide (PaCO2) were measured under conditions of normoxia and severe hypoxia. Chloride cell proliferation on the lamellae significantly increased the water-blood diffusion distance on the 2nd and 7th day in deionized water. VO2 was kept constant until the critical oxygen pressure (PcO2) of 21.6+/-0.9 mmHg in both the control and deionized water fish was reached. The ventilatory parameters were higher in deionized water fish in normoxia, and increased during hypoxia, matching decreases in the water's partial O2 pressure. Impairment of the respiratory function was evidenced by the decrease of PaO2 of deionized water fish in normoxic condition. However, despite the changes in the epithelial morphology of gills in fish kept in deionized water, H. malabaricus proved be a hypoxic-tolerant tropical species.
通过测量热带鱼马拉巴锯脂鲤在常氧和逐渐缺氧过程中的耗氧量（VO2）和通气参数，评估氯化物细胞增殖对呼吸功能的影响。将鱼饲养在去离子水中诱导氯化物细胞增殖，并使用流通式呼吸测定系统在该水中第1天、第2天和第7天测量对呼吸功能的影响。在常氧和严重缺氧条件下测量血浆渗透压以及动脉血氧分压（PaO2）和二氧化碳分压（PaCO2）。在去离子水中饲养的鱼，鳃小片上的氯化物细胞增殖在第2天和第7天显著增加了水-血扩散距离。在对照鱼和去离子水饲养的鱼中，VO2在达到临界氧压（PcO2）21.6±0.9 mmHg之前保持恒定。在常氧状态下，去离子水饲养的鱼的通气参数较高，并且在缺氧期间增加，与水中氧分压的降低相匹配。在常氧条件下去离子水饲养的鱼的PaO2降低证明了呼吸功能受损。然而，尽管饲养在去离子水中的鱼鳃上皮形态发生了变化，但马拉巴锯脂鲤被证明是一种耐缺氧的热带物种。
