Heterocyclic systems containing the pyrimido-2,4-dione ring as selective ligands for the alpha 1-adrenoceptors.

: In the present paper recent results obtained in the field of the alpha 1-adrenoceptor (alpha 1AR) ligands are reported. Syntheses, alpha 1AR binding properties and structure-affinity relationships of tricyclic compounds containing the pyrimido-2,4-dione ring are described. Moreover, preliminary results on the binding properties of some derivatives for the recently cloned alpha 1AR subtypes expressed in COS-7 cells (alpha 1B, alpha 1C, alpha 1D) are discussed. Obtained data clearly indicate that some of the synthesized compounds are able to discriminate between the alpha 1B and the alpha 1C/alpha 1D adrenoceptor subclasses.