PHARMACOLOGICAL STUDIES WITH DERIVATIVES OF 2-AMINOTETRALIN, BENZHYDRO[F]QUINOLINE, BENZHYDRO[G]QUINOLINE, APOMORPHINE AND CLONIDINE SUGGEST A PHARMACOLOGICAL DISSIMILARITY BETWEEN PERIPHERAL PRE-SYNAPTIC DOPAMINE-RECEPTORS AND ALPHA-2 ADRENOCEPTORS .2.

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 224  (2) , 352-358
Abstract
Presynaptic dopamine receptors and .alpha.-2-adrenoceptors are evidently pharmacologically different. A series of 2-aminotetralins, benzhydro[f]quinolines, benzhydro[g]quinolines, apomorphine and clonidine were studied to determine if they could stimulate presynaptic .alpha.-2 adrenoceptor and dopamine receptors in heart and ileum of guinea pigs and cats. Presynaptic dopamine receptor activity was observed in di- and monohydroxy derivatives of 2-aminotetralins, dihydroxy derivatives of benzohydro[g]quinolines and benzohydro[g]quinolines and apomorphine. The greatest presynaptic dopamine receptor activity was observed with agents which maintained the dopamine moiety in the trans coplanar conformation. Monohydroxy derivatives of 2-aminotetralins were devoid of presynaptic .alpha.-2 adrenoceptor activity, and both cis and trans isomers of dihydroxy derivatives of benzohydro[f]quinolines and benzohydro[g]quinolines exhibited significant presynaptic .alpha.-2 adrenoceptors activity. Presynaptic .alpha.-2 adrenoceptors and dopamine receptors evidently represent separate functional entities. A discussion on the structure activity relationship associated with presynaptic .alpha.-2 adrenoceptor and dopamine receptor is provided.