K. Prokai-Tatrai, M. Teixido, V. Nguyen, A. D. Zharikova and L. Prokai Pages 141 - 152 ( 12 )
A metabolically stable and centrally acting analog of pGlu-Glu-Pro-NH2 ([Glu2]TRH, a tripeptide structurally related to TRH (thyrotropin-releasing hormone)) was designed by replacing the amino-terminal pyroglutamyl residue with a pyridinium moiety. The analeptic action of the analog was used to optimize the efficacy of this novel CNS agent when administered intravenously in its CNS-permeable prodrug forms obtained via the reduction of the pyridinium moiety to the nonionic dihydropyridine and esterifying the central Glu with various alcohols. The maximum effect in antagonizing pentobarbital-induced narcosis in mice was achieved with the hexyl ester that was used subsequently for a comparative evaluation with a prodrug of the parent neuropeptide in the Porsolt swim test as a paradigm for antidepressant effect. The novel analog maintained its antidepressant potency but showed reduced analeptic action compared to [Glu2]TRH; thus, an increase in the selectivity of CNS-action was obtained by the incorporation of the pyridinium moiety.
[glu2]trh, central nervous system permeable prodrugs, analeptic effect, antidepressant, porsolt swim test, immobilized artificial membrane chromatography
Department of Medicinal Chemistry, College of Pharmacy, University of Florida, 1600 Archer Road,Gainesville, FL 32610-0485, USA.