The selectivity of newly synthesized ergot derivatives to alpha 1- and alpha 2-adrenoceptors, D1- and D2-dopaminergic receptors, muscarinic acetylcholinoceptors and beta-adrenoceptors.
1. We tested affinities of newly synthesized ergot derivatives to alpha 1- and alpha 2-adrenoceptors, D1- and D2-dopamine receptors, muscarinic acetylcholinoceptors and beta-adrenoceptors using radioligand binding techniques. 2. BAM-1110 was alpha 2-selective, though its affinity to alpha 2-adrenoceptors was one tenth less than that of yohimbine. 3. BAM-1303, which was non-selective, had high affinity to alpha-adrenoceptors. The pKi-values for BAM-1303 was 10.11 against both [3H]prazosin (alpha 1-ligand) and [3H]rauwolscine (alpha 2-ligand). 4. New ergot derivatives were selective to D2-dopamine receptors. BAM-1125 and BAM-1303 had high selectivity to D2-receptors. 5. They had less affinity to muscarinic receptors and beta-adrenoceptors.
Okumura
K
K
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Koike
K
K
Asai
H
H
Takayanagi
I
I
D000818:Animals; D001667:Binding, Competitive; D002540:Cerebral Cortex / Q000378:metabolism; D004876:Ergot Alkaloids / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011954:Receptors, Dopamine / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*
D004876:Ergot Alkaloids; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011954:Receptors, Dopamine; D011976:Receptors, Muscarinic