PROTEIN-KINASE-C AND ION-TRANSPORT IN THE POSTERIOR GILLS OF THE CHINESE CRAB ERIOCHEIR-SINENSIS

The possible involvement of protein kinase C in control of ion transport was investigated on a preparation of isolated, perfused posterior gills of the Chinese crabs Eriocheir sinensis (collected in 1989 from lakes near Emden, northern Germany) acclimated to fresh water. 1-oleyl-2-acetyl-sn-glycerol (OAG) and phorbol 12-myristate 13-acetate (PMA), two activators of protein kinase C, when added to the perfusion saline, induced depolarisation of the transepithelial potential difference (PD) and an increase in transepithelial Na+ influx. The observed increase was proportional to OAG concentration up to 250-mu-M, with a 2.5 x accelerated Na+ influx. OAG and PMA remained without effect on Cl- fluxes. The observed effects were in agreement with an activation, via protein kinase C, of the Na+/K+ ATPase located on the serosal side of the epithelium.