3-(4-Chloro-2-morpholin-4-yl-thiazol-5-yl)-8-(1-ethylpropyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine: a novel brain-penetrant, orally available corticotropin-releasing factor receptor 1 antagonist with efficacy in animal models of alcoholism.

Abstract

We describe a novel corticotropin-releasing factor receptor 1 (CRF1) antagonist with advantageous properties for clinical development, and its in vivo activity in preclinical alcoholism models. 3-(4-Chloro-2-morpholin-4-yl-thiazol-5-yl)-8-(1-ethylpropyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine (MTIP) inhibited 125I-sauvagine binding to rat pituitary membranes and cloned human CRF1 with subnanomolar affinities, with no detectable activity at the CRF2 receptor or other common drug targets. After oral administration to rats, MTIP inhibited 125I-sauvagine binding to rat cerebellar membranes ex vivo with an ED50 of approximately 1.3 mg/kg and an oral bioavailability of 91.1%. Compared with R121919 (2,5-dimethyl-3-(6-dimethyl-4-methylpyridin-3-yl)-7-dipropylamino-pyrazolo[1,5-a]pyrimidine) and CP154526 (N-butyl-N-ethyl-4,9-dimethyl-7-(2,4,6-trimethylphenyl)-3,5,7-triazabicyclo[4.3.0]nona-2,4,8,10-tetraen-2-amine), MTIP had a markedly reduced volume of distribution and clearance. Neither open-field activity nor baseline exploration of an elevated plus-maze was affected by MTIP (1-10 mg/kg). In contrast, MTIP dose-dependently reversed anxiogenic effects of withdrawal from a 3 g/kg alcohol dose. Similarly, MTIP blocked excessive alcohol self-administration in Wistar rats with a history of dependence, and in a genetic model of high alcohol preference, the msP rat, at doses that had no effect in nondependent Wistar rats. Also, MTIP blocked reinstatement of stress-induced alcohol seeking both in postdependent and in genetically selected msP animals, again at doses that were ineffective in nondependent Wistar rats. Based on these findings, MTIP is a promising candidate for treatment of alcohol dependence.

• Authors: Donald R Gehlert, Andrea Cippitelli, Annika Thorsell, Anh Dzung Lê, Philip A Hipskind, Chafiq Hamdouchi, Jianliang Lu, Erik J Hembre, Jeffrey Cramer, Min Song, David McKinzie, Michelle Morin, Roberto Ciccocioppo, Markus Heilig
• Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci) Vol. 27 Issue 10 Pg. 2718-26 (Mar 07 2007) ISSN: 1529-2401 [Electronic] United States
• PMID: 17344409 (Publication Type: Journal Article)

Chemical References

• 3-(4-chloro-2-morpholin-4-ylthiazol-5-yl)-8-(1-ethylpropyl)-2,6-dimethylimidazo(1,2-b)pyridazine
• Amphibian Proteins
• Peptide Hormones
• Peptides
• Pyridazines
• Receptors, Corticotropin-Releasing Hormone
• Thiazoles
• Ethanol
• CRF receptor type 1
• sauvagine

Topics

• Administration, Oral
• Alcohol Drinking (psychology)
• Alcoholism (drug therapy, genetics, psychology)
• Amphibian Proteins
• Animals
• Anxiety (psychology)
• Behavior, Animal (drug effects)
• Brain (metabolism)
• Cerebellum (drug effects, metabolism)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Ethanol (administration & dosage)
• Male
• Peptide Hormones
• Peptides (antagonists & inhibitors, metabolism)
• Pituitary Gland (drug effects, metabolism)
• Pyridazines (administration & dosage, pharmacokinetics, therapeutic use)
• Rats
• Rats, Sprague-Dawley
• Rats, Wistar
• Receptors, Corticotropin-Releasing Hormone (antagonists & inhibitors)
• Self Administration
• Stress, Physiological (psychology)
• Substance Withdrawal Syndrome (psychology)
• Thiazoles (administration & dosage, pharmacokinetics, therapeutic use)