The sodium and chloride dependence of chloride secretion by the opercular epithelium

✍ Scribed by Degnan, Kevin J.

• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 548 KB
• Volume: 231
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402310103

✦ Synopsis

Abstract

The effects of ion substitutions on the Cl^−^ secretion rate and tissue conductance of isolated short‐circuited opercular epithelia from sea‐water‐adapted Fundulus heteroclitus were investigated. Serosal Na^+^ substitution had the same effect on the Cl^−^ secretion rate that serosal Cl^−^ substitution had on the active component of the Cl^−^ efflux. This similarity indicated a 1:1 Na‐Cl requirement for active Cl^−^ secretion across this epithelium, which supports the proposal of a coupled NaCl uptake mechanism at the serosal membrane of Cl^−^ secretory epithelia. Mucosal Na^+^ and Cl^−^ substitutions appeared to inhibit completely the active Cl^−^ secretory flux. The reductions in the tissue conductance with mucosal ion substitutions suggested that this effect can be attributed to a blocking of the apical membrane Cl^−^ conductance. These mucosal ion effects suggested a possible direct regulatory influence of the external salinity on the Cl^−^ secretion rate and tissue conductance, which provide alternative explanations for observations with the teleost gill epithelium.