Re-examination of [3H]mepyramine binding assay for histamine H1 receptor using quinine

Biochem Biophys Res Commun. 1992 Nov 30;189(1):378-84. doi: 10.1016/0006-291x(92)91569-c.


[3H]Mepyramine, a potent antagonist of the histamine H1 receptor, has been widely used as a radioligand binding assay for the H1 receptor. Previously, we purified a mepyramine binding protein (MBP) from rat liver, but found that its partial amino acid sequences were very similar to those of debrisoquine 4-hydroxylase isozymes (P450 db1 and db2), which are members of the superfamily of cytochrome P450. Using cloned histamine H1 receptor cDNA, we found that [3H]mepyramine could bind only the H1 receptor and did not bind MBP in the presence of 10(-5) M quinine, an inhibitor of debrisoquine 4-hydroxylase isozymes. We developed a method to determine the contents of the H1 receptor and MBP separately using [3H]mepyramine and quinine and found that MBP is abundant in certain areas of bovine brain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding, Competitive
  • Brain / metabolism*
  • Cattle
  • Cell Membrane / metabolism
  • Glioma
  • Kinetics
  • Liver / metabolism*
  • Organ Specificity
  • Pyrilamine / metabolism*
  • Quinine / pharmacology*
  • Radioligand Assay / methods
  • Rats
  • Receptors, Histamine H1 / analysis*
  • Receptors, Histamine H1 / genetics
  • Receptors, Histamine H1 / metabolism
  • Transfection
  • Tritium
  • Tumor Cells, Cultured


  • Receptors, Histamine H1
  • Tritium
  • Quinine
  • Pyrilamine