Transepithelial potential differences and Na+ flux in isolated perfused gills of the crab Chasmagnathus granulatus (Grapsidae) acclimated to hyper- and hypo-salinity

LUQUET C. M.; POSTEL U.; HALPERIN J.; URCOLA M.R.

JOURNAL OF EXPERIMENTAL BIOLOGY

COMPANY OF BIOLOGISTS LTD

Lugar: Cambridge; Año: 2002 vol. 205 p. 71 - 77

0022-0949

We studied the transepithelial potential difference (TEPD)and 22Na flux across isolated perfused gills (anterior pair 5 and posteriorpairs 6?8) of the crab Chasmagnathus granulatus acclimated to eitherhypo- or hyper-osmotic conditions.The gills of crabs acclimated to low salinity,perfused and bathed with 10 ? saline solutions, produced the following TEPDs(hemolymph side with respect to bath side): 0.4±0.7, ?10.2±1.6, ?10.8±1.3 and ?6.7±1.3mV for gills 5, 6, 7 and 8, respectively. Gills 6, 7 and 8 did not differsignificantly. Reducing the saline concentration of bath and perfusate from 30 ?to 20 ? or 10 ? increased significantly the TEPDs of these gills. TEPDs of gill6 (representative of posterior gills) were reduced by 69±5% and 60±5% afterperfusion with ouabain or BaCl2 (5mmoll?1 each), respectively. The same gillshowed a net ouabain-sensitive Na+ influx of 1150±290 mequiv g?1 h?1.Gill 6 of crabs acclimated to high salinity producedTEPDs of ?1.5±0.1 and ?1.3±0.09 mV after perfusion with 30 ? or 40 ? salines,respectively. Perfusion with ouabain or BaCl2 reduced TEPDs by 76±7% and 86±4%,respectively. A net ouabain-sensitive Na+ efflux of 2282±337 mequiv g?1h?1was recorded in gill 6 perfused with 38 ? saline.