[Interaction of tetrahydroisoquinolines and 3-aminotetralines with opioid mu-receptors].

The interaction of the tetrahydroisoquinoline (THIQ) and 3-aminotetraline (3-AT derivatives with opioid mu-receptors has been studied. It is shown that THIQ and 3-AT derivatives bind to a site on the mu-receptor which these compounds are likely to share with "classical" opiates, whose structure also includes the 3-AT group. The binding site for nonpeptide substances is in a strong allosteric interaction with the binding site for enkephalins. Some biological effects of THIQ and 3-AT derivatives can be explained in terms of their interaction with opioid receptors. One may speculate that the evolution of the endogenous opioid receptor ligands proceeded from simple 3-AT derivatives towards morphinans and, probably, benzomorphans.