Stereoselective blockade of alpha-adrenoceptors by berbine derivatives |
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Authors: | C Schott L Tetsi C Heitz J F Stambach L Jung J C Stoclet |
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Institution: | Unité de Pharmacologie Cellulaire et Moléculaire, Université Louis Pasteur, Strasbourg, France. |
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Abstract: | The effects of the two enantiomers of berbine (5,6,13,13a-tetrahydro-8H-dibenzoa,g]quinolizine) and of derivatives obtained by introducing various substitutions on aromatic rings were investigated on alpha 1- or alpha 2-adrenoceptor subtypes. Binding studies carried out on rat cerebral cortex membranes using 3H]prazosin or 3H]yohimbine showed that the affinities of the (+) and (-)enantiomers for alpha 1 and alpha 2 binding sites were different and were differently modified by substitutions added to the berbine nucleus, leading to alpha 1- and alpha 2-selective compounds. Experiments performed on the isolated rat aorta and in pithed rats in vivo demonstrated the alpha-blocking property of berbine derivatives and confirmed the stereoselectivity of the effects of the (+) and (-)enantiomers on alpha 1- and alpha 2-adrenoceptor subtypes. |
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