Cell volume regulation following hypotonic stress in the intestine of the eel, Anguilla anguilla, is Ca²⁺-dependent

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• 作者：Trischitta ; Francesca ; Denaro ; Maria Gabriella ; Faggio ; Caterina
• 关键词：Fish intestine ; Regulatory volume decrease ; Ca²⁺ ; K⁺ channels
• 刊名：Comparative Biochemistry and Physiology, Part B
• 出版年：2005
• 出版时间：March, 2005
• 年：2005
• 卷：140
• 期：3
• 页码：359-367
• 全文大小：417 K

文摘

The involvement of Ca²⁺ in the regulatory volume decrease (RVD) mechanism was studied in both isolated enterocytes and intestine of the eel, Anguilla anguilla. Videometric methods and electrophysiological techniques were respectively employed. The isolated enterocytes rapidly swelled following a change from isotonic (315 mOsm/kg) to hypotonic (180 mOsm/kg) saline solutions. Afterwards, they tended to recover their original size. This homeostatic response was inhibited both in the absence of extracellular Ca²⁺ and in the presence of TMB8, an inhibitor of Ca²⁺ release from intracellular stores. It is likely that Ca²⁺ entry through verapamil-sensitive Ca²⁺ channels is responsible for RVD since the blocker impaired the ability of the cell to recover its volume after the hypotonic shock. The observation that a 10-fold increase of K⁺ concentration as well as the presence of quinine in the hypotonic solution completely abolished RVD indicated the involvement of K⁺ in this response. Experiments performed with the isolated intestine suggested that the opening of basolateral K⁺ channels facilitates K⁺ loss (and hence water efflux) from the cell during RVD and that this opening is probably due to Ca²⁺ entry into the cell through both the mucosal and the serosal membranes.