Ong, J.Kerr, D.Ansar, M.Vaccher, C.Berthelot, P.2006-06-232006-06-231998Canadian Journal of Physiology and Pharmacology, 1998; 76(7-8):798-8010008-42121205-7541http://hdl.handle.net/2440/5958(R,S)-4-Amino-3-(7-methylbenzo[b]furan-2-yl)-butanoic acid (7-MBFG), a new benzofuran analogue of the GABA(B) receptor agonist baclofen, has been evaluated for pharmacological activity on GABA(B) receptors in the guinea-pig isolated ileum and rat neocortical slices. 7-MBFG (300 and 500 microM) reversibly antagonized the (R,S)-baclofen induced depression of cholinergic twitch contractions in the guinea-pig ileum and shifted the concentration-response curve for baclofen to the right, in a parallel manner, giving an apparent pA2 value of 3.7+/-0.3. Likewise, 7-MBFG (300 and 500 microM) reversibly blocked the baclofen-induced suppression of spontaneous discharges, in rat neocortical slices maintained in Mg2+ -free Krebs medium, and caused a rightward, parallel shift of the baclofen concentration-response curve, giving an apparent pA2 value of 4.1+/-0.1. The compound 7-MBFG belongs to a novel, new class of antagonist at central and peripheral GABA(B) receptors, in which the antagonist properties reside in the pseudo-aromatic character of their 3-benzo[b]furan-2-yl substituents, and might provide useful leads for further development of GABA(B) receptor ligands.enMuscle, SmoothIleumNeocortexAnimalsGuinea PigsRatsRats, Sprague-DawleyBaclofenButyratesBenzofuransGABA AntagonistsMuscle ContractionDose-Response Relationship, DrugMaleGABA-B Receptor AntagonistsIn Vitro TechniquesJournal article0030006094001998063410.1139/cjpp-76-7-8-7982-s2.0-003244947570100Ong, J. [0000-0002-0958-460X]