Pharmacological profile of FK480, a novel cholecystokinin type-A receptor antagonist: Comparison to loxiglumide

H. Ito*, H. Sogabe, T. Nakarai, Y. Sato, M. Tomoi, M. Kadowaki, M. Matsuo, K. Tokoro, K. Yoshida

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

The pharmacological profile of FK480[(S)-(+)-N-<1-(2)-fluorophenyl)- 3,4,6,7-tetra hydro-4-oxo-pyrrolo(3,2,1-jk) (1,4)benzodiaze-pine-3-yl>-1H- indole-2-carboxamide], a novel cholecystokinin type-A (CCK-A) receptor antagonist, was compared with that of the CCK-A receptor antagonist, loxiglumide. Both FK480 and loxiglumide inhibited 125I-labeled CCK-8 (125I-CCK-8) binding to rat pancreatic and guinea-pig gallbladder membranes with IC50 values of 0.40 ± 0.04 and 0.06 ± 0.02 nM for FK480 and 330 ± 66 and 66 ± 10 nM for loxiglumide, respectively. These two agents also inhibited 125I-CCK-8 binding to guinea-pig brain (cerebral cortex) receptors with respective IC50 values of 72 ± 11 nM and >10 μM, indicating less affinity to central receptors. Intravenous administration of FK480 (ED50 = 18 μg/kg) was 2800 times more potent than that of loxiglumide (ED50 = 50 mg/kg) in inhibiting CCK-8-induced pancreatic amylase secretion in rats. Furthermore, FK480 had ED50 values of 10 and 8.4 μg/kg, respectively, in antagonizing CCK-8-induced inhibition of charcoal meal gastric emptying in mice when administered orally 1 or 5 hr before the CCK-8. Loxiglumide (ED50 = 23.5 mg/kg, when administered orally 1 hr before the CCK-8) also antagonized it, but its activity was 2400 times less than that of FK480. We conclude that FK480 is a potent, orally effective CCK-A receptor antagonist with long duration of action.

Original languageEnglish
Pages (from-to)571-575
Number of pages5
JournalJournal of Pharmacology and Experimental Therapeutics
Volume268
Issue number2
DOIs
StatePublished - 1994

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

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