Chloride conductance and mitochondria-rich cell density in isolated skin of Rana catesbeiana acclimated to various environments
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- 作者：Claro de Toledo ; Manuel ; Malheiros Lopes Sanioto ; Sonia
- 关键词：Ion transport ; Transepithelial conductance ; Frog skin ; Mitochondria-rich cell density ; Rana catesbeiana ; Isolated skin ; Paracellular pathway ; Frog acclimation ; Tight junction regulation
- 刊名：Comparative Biochemistry and Physiology, Part B
- 出版年：2002
- 出版时间：August, 2002
- 年：2002
- 卷：132
- 期：4
- 页码：791-799
- 全文大小：441 K
文摘
The Cl<sup>−sup> conductance in isolated skin of frogs (Rana catesbeiana) acclimated to 30 mM solutions of NaCl, Na<sub>2sub>SO<sub>4sub>, MgCl<sub>2sub> and distilled water (DW) was studied. Transepithelial potential difference (PD<sub>transsub>), short-circuit current (I<sub>SCsub>) and total conductance (G<sub>tsub>) were measured under conditions such that there was Cl<sup>−sup> flux in the presence and absence of Na<sup>+sup> transport. The Cl<sup>−sup> content of the mucosal solution was acutely replaced with SO<sub>4sub><sup>2−sup> or gluconate to evaluate the effect of removal of Cl<sup>−sup> conductance on electrophysiological parameters. Mitochondria-rich cell density (D<sub>MRCsub>) was also measured. Skins from frogs acclimated to NaCl and Na<sub>2sub>SO<sub>4sub> showed the lowest and the highest D<sub>MRCsub>, respectively, but no difference could be found between the skins from frogs acclimated to DW and MgCl<sub>2sub> indicating that D<sub>MRCsub> is not unconditionally dependent on environmental Cl<sup>−sup> in this species. Frogs acclimated to NaCl showed marked differences when compared to the other groups: the highest G<sub>tsub>, probably represented by a higher paracellular conductance; the lowest transepithelial electrical potential difference which remained invariant after replacement of mucosal Cl<sup>−sup> with SO<sub>4sub><sup>2−sup> or replacement of mucosal Cl<sup>−sup> with gluconate and an inwardly oriented positive current in the absence of bilateral Na<sup>+sup>.