The action of lanthanum and manganese on anaphylactic histamine secretion

1. In the concentration range 1 nM to 1 muM, lanthanum inhibited the calcium-dependent component of anaphylactic histamine release, but was without effect on the component which was independent of calcium.2. The inhibition of anaphylactic histamine release by lanthanum can be reversed by increasing the calcium ion concentration. The pA(2) for the lanthanum-receptor interaction was found to be 7.6.3. Lanthanum also inhibited the activation of anaphylactic histamine release by strontium ions.4. The inhibition of anaphylactic histamine release by lanthanum was reversed by eluting the lanthanum from the cells.5. In the concentration range 1 to 300 nM, lanthanum had no effect on the histamine release induced by compound 48/80 in a calcium-free medium, but the effect of calcium on the istamine release by compound 48/80 was antagonized by lanthanum in this range of concentrations.6. At concentrations of 10 muM and greater, lanthanum induced a release of histamine in the absence of antigen.7. In the concentration range 0.5 to 4.0 mM, manganese inhibited the calcium-dependent component of anaphylactic histamine release, but was without effect on the component which is independent of calcium. The inhibition of anaphylactic histamine release by manganese could be reversed by increasing the calcium ion concentration.