Conformational analysis of five I1-receptor agonists in the neutral form (clonidine,moxonidine, rilmenidine,phentolamine,and phencyclidine)and one antagonist of I1-receptors (idazoxane)was carried out by means of the MM2 method.Structures of stable conformations of individual compounds were fully optimised.Degree of similarity of stable conformations was visualized.The proton affinities and lipophilicities of title compounds were also computed.It is obvious that all studied drugs except phencyclidine are able to occupy the same space.An important role for affinity of studied drugs towards I1-receptors can be played by their different hydrophobicity (logP =1 až 2).

        Key words: I1-Imidazoline receptors – antihypertensives – conformational analysis – clonidine –moxonidine –rilmenidine – phentolamine –phencyclidine