Vibrio cholerae haemolysin: genetic constitution and biotype

voltage-gated K channels in other cell types [Ba 2 mM; Cs 5 mM; TEA (tetraethylammonium) 20 mM; EGTA 1 mM) (Lew & Ferreira, 1978; Egan et ul., 1987) did not, however, alter ouabainand bumetanide-insensitive K uptake. The substitution of CH,SO, for CI in the incubation medium reduced the residual K uptake by about 18%, suggesting that a Cldependent K transport pathway similar to that observed in other cell types (Hoffmann, 1986) might be present. Thus, in common with other cell types, K uptake in chondrocytes is mediated partly by the Na/K pump and (Na + K) co-transport pathways, although there are other pathways present in chondrocytes which are still to be defined. The pericellular environment of chondrocytes in loadbearing cartilages is constantly changing as fluid is pumped into and out of the tissue (Urban & Bavliss. 1987). The physiologically relevant to chondrocytes, since they are surrounded by a pericellular environment, the osmolality of which is considerably greater than that of conventional incubation media.