N-substituted piperidinyl alkyl imidazoles: discovery of methimepip as a potent and selective histamine H3 receptor agonist

  • J Med Chem. 2005 Mar 24;48(6):2100-7. doi: 10.1021/jm049475h.
Ruengwit Kitbunnadaj  1 ,  Takeshi Hashimoto ,  Enzo Poli ,  Obbe P Zuiderveld ,  Alessandro Menozzi ,  Ryoko Hidaka ,  Iwan J P de Esch ,  Remko A Bakker ,  Wiro M P B Menge ,  Atsushi Yamatodani ,  Gabriella Coruzzi ,  Henk Timmerman ,  Rob Leurs
Affiliations
  • 1. Faculty of Chemistry, Department of Pharmacochemistry, Division of Medicinal Chemistry, Leiden/Amsterdam Center of Drug Research, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
PMID: 15771452 DOI: 10.1021/jm049475h
Abstract

In this study, we continue our efforts toward the development of potent and highly selective histamine H(3) receptor agonists. We introduced various alkyl or aryl alkyl groups on the piperidine nitrogen of the known H(3)/H(4) agonist immepip and its analogues (1-3a). We observed that N-methyl-substituted immepip (methimepip) exhibits high affinity and agonist activity at the human histamine H(3) receptor (pK(i) = 9.0 and pEC(50) = 9.5) with a 2000-fold selectivity at the human H(3) receptor over the human H(4) receptor and more than a 10000-fold selectivity over the human histamine H(1) and H(2) receptors. Methimepip was also very effective as an H(3) receptor agonist at the guinea pig ileum (pD(2) = 8.26). Moreover, in vivo microdialysis (in rat brain) showed that methimepip reduces the basal level of brain histamine to about 25% after a 5 mg/kg intraperitoneal administration.

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