PERFUSION OF GILLS ISOLATED FROM THE HYPER-HYPOREGULATING CRAB PACHYGRAPSUS-MARMORATUS (CRUSTACEA, DECAPODA) - ADAPTATION OF A METHOD

This paper reports the adaptation of a branchial perfusion technique t o the gills of the small hyper-hyporegulating crab, Pachygrapsus marmo ratus. The physiological quality of the preparation has been establish ed and preliminary measurements of the transepithelial potential diffe rence (PD) and sodium fluxes were reported. A clear-cut distinction ha s to be made between anterior and posterior gills. With symmetrical ba thing conditions (same saline on both sides of the epithelium), a sign ificant transepithelial PD was measured only in posterior gills isolat ed from crabs acclimated to dilute sea water. This hemolymph-side nega tive PD is shown to require biological energy and to be sensitive to o uabain. Na+ influx was larger than efflux, indicating the occurrence o f a net inward of Na+. The active nature of the Na+ influx was establi shed.