Binding profile of the selective muscarinic receptor antagonist tripitramine

Eur J Pharmacol. 1994 Aug 16;268(3):459-62. doi: 10.1016/0922-4106(94)90075-2.


The binding selectivity of the muscarinic antagonist tripitramine has been tested on the five cloned human muscarinic receptor subtypes (Hm1 to Hm5) expressed in chinese hamster ovary (CHO-K1) cells. The results indicate that tripitramine binds to the muscarinic Hm2 receptor with a Ki value of 0.27 +/- 0.02 nM. Tripitramine distinguishes Hm2 vs. Hm4 by a factor of 24 and vs. Hm3 and Hm5 by a factor of 142 and 125, respectively. A lower affinity ratio, about 6-fold, was found between muscarinic Hm2 and Hm1 receptors. A comparative study with the well-known selective muscarinic M2 receptor antagonist methoctramine indicates that tripitramine has gained both potency and selectivity for the muscarinic Hm2 receptor subtype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzodiazepines / metabolism*
  • CHO Cells
  • Cricetinae
  • DNA, Complementary / metabolism
  • Diamines / metabolism
  • Humans
  • Ligands
  • Muscarinic Antagonists
  • N-Methylscopolamine
  • Parasympatholytics / metabolism
  • Receptors, Muscarinic / genetics
  • Receptors, Muscarinic / metabolism*
  • Scopolamine Derivatives / pharmacokinetics
  • Thermodynamics


  • DNA, Complementary
  • Diamines
  • Ligands
  • Muscarinic Antagonists
  • Parasympatholytics
  • Receptors, Muscarinic
  • Scopolamine Derivatives
  • Benzodiazepines
  • tripitramine
  • methoctramine
  • N-Methylscopolamine