STRUCTURE AFFINITY RELATIONSHIPS OF BERBINES OR 5,6,13,13A-TETRAHYDRO-8H-DIBENZO[A,G]QUINOLIZINES AT ALPHA-ADRENOCEPTORS

The synthesis of some derivatives of tetrahydro-8H-dibenzo[a,g]quinolizines or berbines is described. A pharmacological study was carried out at alpha-1 and alpha-2-adrenoceptors using radioligand binding techniques. This study has shown that the aromatic ring A is responsible for the alpha-2-affinity of berbines. Furthermore, the aromatic ring D is important for alpha-1-affinity. However, in this case, it seems that the planarity of the molecule is a very important structural parameter for affinity. The role of the nitrogen atom is also discussed. A conformational analysis of the partial saturated berbines was established by a C-13 NMR study.