摘要:
Aim of the present study was to obtain novel alpha(2)-adrenoreceptor (alpha(2)-AR) antagonists, possibly endowed with subtype-selectivity. Therefore, inspired by the non subtype-selective alpha(2)-AR antagonist idazoxan, we designed 1,4-dioxane derivatives bearing an aromatic area in position 5 or 6 and the imidazoline nucleus in position 2. Among the novel molecules 1-6, compound 2, with a trans stereochemical relationship between 5-phenyl and 2-imidazoline groups, was able to antagonize the sole alpha(2A)-subtype. Moreover, 2 showed an affinity at I-2-imidazoline binding sites (I-2-IBS) comparable to that at alpha(2A)-AR. In in vivo studies 2 strongly increased morphine analgesia. This interesting behaviour appeared to be induced by the favourable involvement of alpha(2A)-AR antagonism in the I-2-IBS-mediated morphine analgesia enhancement. (C) 2012 Elsevier Ltd. All rights reserved.