A series of novel imidazoline I 2-receptor selective Schiff bases of 1-(benzylidenamino)-3,3-dimethylguanidine

Abstract

A series of 12 Schiff bases of 1-(benzylidenamino)-3,3-dimethylguanidine were evaluated for their affinities at imidazoline I 2-receptors and α 2-adrenoceptors in the guinea pig cerebral cortex by using a 2-curve assay with [ 3H]idazoxan as ligand and the simultaneous computer analysis of (−)adrenaline masked and non-masked competition curves. All of the dimethylguanidines were selective for I 2-receptors with the selectivity ranging 6–110-fold, and the most selective being WAP8 (2-bromobenzylidenamino-3,3-dimethylguanidine) closely followed by FLA151 (2-chlorobenzylidenamino-3,3-dimethylguanidine). Some of the dimethylguanidines were also tested for affinity at bovine kidney cortex I 2-receptors and guinea pig α 1-adrenoceptors. These substnces were found to have similar affinities for bovine kidney I 2-receptors as for guinea pig cerebral cortex I 2-receptors, but their affinities for the α 1-adrenoceptors were considerably lower.