High specific activity tritiation of various methylated histamine analogues

It has been nearly 110 years since the discovery of histamine and its profound physiological actions as well as the four distinct binding sites that constitute its receptor family. Histamine agonists and antagonists when labelled with tritium have been very valuable in advancing our understanding of histamine receptors. Over the years, scores of histamine receptor ligands have been tritiated but few if any have been methylated derivatives of histamine. For that reason, this paper describes the tritiation of several methylated histamine analogues as well as their analytical characterization by HPLC, MS and tritium NMR.