‘In Vitro’ Preparation of Crab Gill for Use in Ion Transport Studies

Gill is the organ chiefly responsible for osmoregulation of blood in crabs, but not all species have this ability (KROGH, 1939). In some crabs, osmoregulation is well developed and the concentration of sodium chloride in the blood is maintained at relatively constant levels when the animals invade brackish and even fresh water (SHAW, 1961~ and b, 1963; WEBB, 1940). In other crabs, regulation does not occur and these animals are sharply limited to a marine environment. A comparison of the transport of salt in gills of marine, non-regulating crabs with that in gills of euryhaline, regulating crabs should enhance our understanding of the development of osmoregulatory mechanisms. For this purpose, an in vitro preparation of gills, perfused with a balanced, isotonic salt solution has been developed. In this preparation it is possible to measure both the ionic fluxes and the associated changes in the electrical potential. We report here the method of preparation and some results on the transport of sodium in gills of Muja sqtiinudo Risso, a marine crab and of Curcinus maenus (L.), a euryhaline shore crab.