Labeling of histamine H₁-receptors in vivo: A compartment model analysis and positron emission tomographic imaging

Binding of [³H]-pyrilamine to guinea-pig brain in vivo was studied and analyzed kinetically on the basis of a four-compartment model to establish the method of analysis for the in vivo binding. The pharmacological properties of the [³H]-pyrilamine binding in vivo were similar to those of the in vitro binding to brain homogenate. The distribution of histamine H₁-receptors in dog brain, which was obtained by positron emission tomography (PET) with [¹¹C]pyrilamine or doxepin as a tracer, was in good correlation to that obtained by the in vitro binding method. We finally applied this in vivo binding method to a living healthy human to reveal the distribution of H₁-receptor in the brain.