Changes of ligand binding after membrane phosphorylation.

Phosphorylation of synaptic plasma brain membranes (SPM) causes a decrease of the specific binding of demethylated tricyclic antidepressants (TCA) and changes the affinity of 3H-imipramine and 3H-desmethylimipramine binding. The decrease of TCA binding was found also in lymphocyte membranes. In platelet membranes a decreased binding was found only with demethylated dibenzazepine derivatives. Bmax and Kd values are also decreased in the presence of phosphatidic acid or alpha-glycerolphosphate.