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ID: ALA3797164

Journal: Eur J Med Chem

Title: Transfer of SAR information from hypotensive indazole to indole derivatives acting at α-adrenergic receptors: In vitro and in vivo studies.

Authors: Sączewski J, Hudson A, Scheinin M, Wasilewska A, Sączewski F, Rybczyńska A, Ferdousi M, Laurila JM, Boblewski K, Lehmann A, Watts H, Ma D.

Abstract: In a search for novel antihypertensive drugs we applied scaffold hopping from the previously described α1-adrenergic receptor antagonists, 1-[(imidazolin-2-yl)methyl]indazoles. The aim was to investigate whether the α-adrenergic properties of the indazole core were transferable to the indole core. The newly obtained 1-[(imidazolin-2-yl)methyl]indole analogues were screened in vitro for their binding affinities for α1-and α2-adrenoceptors, which allowed the identification of the target-based SAR transfer (T_SAR transfer) as well as structure-based SAR transfer (S_SAR transfer) events. However, when screened in vivo with use of anaesthetized male Wistar rats, the new indole ligands showed a different hemodynamic profile than expected. Instead of the immediate hypotensive effect characteristic of peripheral vasodilatator α1 blockers, a biphasic effect was observed, reminiscent of clonidine-like centrally acting antihypertensive agents. This was supported by subsequent in vitro functional studies in [(35)S]GTPγS binding assay, where the indole analogues displayed partial agonist properties at α2-adrenergic receptors. Since no correlation was found between the in vitro binding to α-adrenoceptors and the in vivo hemodynamic effects of the two series of indazole and indole bioisosteric compounds, in a search for new imidazoline-containing adrenergic drugs, the structure-based SAR transfer information obtained from in vitro binding studies should be treated with caution.

CiteXplore: 27031216

DOI: 10.1016/j.ejmech.2016.03.026