title: Effects of divalent cations on amino acid and divalent cation fluxes in gills of the bivalve mollusc, Mytilus californianus.
abstract: Effects of the deletion of Ca++, Mg++, or Ca++ and Mg++ on the leakage of primary amines, Ca++, and Mg++ from gills of Mytilus californianus were studied. In the absence of Ca++ the gills leak primary amines and Ca++ for about 30 minutes, after which the primary amines are reabsorbed. In the absence of Mg++ the gills leak primary amines, with no net reabsorption for at least 90 minutes, and show rapid leakage of Mg++. In the absence of both Ca++ and Mg++ amino acid leakage is initially less than in the absence of only one of the cations. Measurements of the kinetics of leakages of Ca++ and Mg++ are consistent with the hypothesis that both ions are associated with the cell surface, but the affinity of Ca++ for the cell surface is greater than that of Mg++. In the absence of Mg++, the influx of 14C-glycine was depressed to about 1/3 that seen in controls, while deletion of Ca++ had no effect on the rate of influx. Increasing the [Mg++] stepwise between 5 x 10(-6) and 1 x 10(-1) M results in a sigmoidal increase in the rate of influx of 14C-glycine and a hyperbolic increase in the y-intercept of influx curves.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D049872:Bivalvia; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D005880:Gills / Q000378:metabolism*; D005998:Glycine / Q000378:metabolism; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D008274:Magnesium; D002118:Calcium; D005998:Glycine