The Role and Regulation of Chloride Cells in Antarctic Fish

南极鱼类氯细胞的作用和调节

• 批准号: 9613738
• 负责人: David Petzel
• 金额: $ 11.44万
• 依托单位: Creighton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 2001-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9613738&HistoricalAwards=false
• 关键词: Role; Regulation; Chloride; Cells; Antarctic

9613738 Petzel Antarctic fish have the highest serum osmolality of any seawater teleost. Maintenance of fluid balance is crucial for survival. Upon warm acclimation from -1.5o to 4oC the fish lmse 20% of their serum osmolality through extrusion of NaC1 across the gill. NaC1 extrusion in fish is primarily performed by chloride-secreting cells located on the gill arches and gill opercula. The driving force for NaC1 transport is the Na/K-ATPase. To date, no information is available concerning role and regulation of the elevated serum osmolarity in Antarctic fish. Questions which arise include: What role does the chloride cell play in mediating salt extrusion? Which hormones regulate chloride cell activity? The chloride cell physiology and regulation in Antarctic fish will be compared with a New Zealand fish which is eurythermal. The goals of the proposed research are to determine the plasticity of Antarctic and New Zealand fish gill function at the physiological level (through studies of ion transport activity) and molecular level (through studies of the Na/K-ATPase enzyme), specifically this research will: 1) determine the gill extrusion mechanisms underlying the increase in gill Na/K-ATPase activity upon warm acclimation in Antarctic fish and 2) determine the hormonal regulation of the gill extrusion mechanisms. Previously it was shown that upon warming of Antarctic fish there is an increase in NaC1 extrusion as a result of increases in gill total Na/K-ATPase enzyme levels. The proposed experiments will measure chloride cell morphology, metabolism, physiolmgy and regulation in parallel with effects of warming and cooling on the whole fish. Measurements of chloride cell morphology will include changes in diameter and number of cells at different temperatures. In order to ascertain the role of Na/K-ATPase in mediating the enhanced salt extrusion upon warming, we will measure total enzyme activity and total number of enzymes. The role of the chlor ide cell in transport of C1 and Na will assayed by placing the gill opercula sheet epithelia in Using chambers to determine the influence of fish warming on short-circuit current, which is a direct measurement of chloride transport through chloride cells. Finally, regulation of chloride cell function will be determined by altering palsma levels cortisol, prolactin and endogenous endocrines. The results from the proposed experiments will, for the first time, describe in detail the underlying mechanism(s) mediating the enhance hypo-osmoregulation observed in Antarctic fish and will allow the comparison of these results to those observed in a eurythermal New Zealand fish.

Petzel南极鱼具有任何海水硬骨鱼中最高的血清渗透压。 维持体液平衡对生存至关重要。 在从-1.5 ° C到4 ° C的温暖适应后，鱼通过将NaCl挤出鳃而使其血清渗透压降低20%。 NaCl在鱼类中的排出主要由位于鳃弓和鳃盖上的氯化物分泌细胞进行。 NaCl运输的驱动力是Na/K-ATP酶。 到目前为止，没有任何资料是关于南极鱼类血清渗透压升高的作用和调节。 由此产生的问题包括：氯细胞在介导盐挤出中起什么作用？ 哪些激素调节氯细胞活性？ 南极鱼类的氯细胞生理和调节将与新西兰的广温鱼类进行比较。 这项研究的目的是在生理水平上确定南极和新西兰鱼类鳃功能的可塑性（通过离子转运活性的研究）和分子水平（通过研究Na/K-ATP酶），具体而言，本研究将：1）确定南极鱼在温暖驯化后鳃Na/K-ATPase活性增加的鳃挤压机制，以及2）确定激素调节鳃挤出机制。以前，它表明，在南极鱼变暖时，有一个增加的NaCl挤出作为鳃总Na/K-ATP酶水平的增加的结果。 拟议的实验将测量氯细胞形态，代谢，生理和调节平行的升温和降温对整个鱼的影响。 氯细胞形态的测量将包括不同温度下细胞直径和数量的变化。 为了确定Na/K-ATP酶在介导升温后盐挤出增强中的作用，我们将测量总酶活性和酶的总数。 将鳃盖片上皮细胞置于恒温箱中，测定鱼体升温对短路电流的影响，以直接测定氯离子通过氯细胞的转运，从而探讨氯离子细胞在氯离子和钠离子转运中的作用。 最后，氯细胞功能的调节将通过改变脉搏水平皮质醇，催乳素和内源性内分泌来确定。 拟议实验的结果将首次详细描述在南极鱼类中观察到的介导增强低体温调节的基本机制，并将这些结果与在新西兰广温鱼类中观察到的结果进行比较。