Chronic antidepressant treatment enhances agonist affinity of brain alpha 1-adrenoceptors.
Binding of [3H]prazosin, a selective alpha 1-adrenoceptor antagonist, to thalamic membranes was studied following chronic treatment of rats with tricyclic antidepressants. Rosenthal analysis showed no change in the number or affinity of antagonist binding sites; however, the ability of the alpha 1-agonist phenylephrine to compete for these sites was significantly enhanced after chronic tricyclic treatment. This result is consistent with previous studies showing physiological alpha 1-supersensitivity in thalamus after chronic antidepressant administration.
D000639:Amitriptyline / Q000494:pharmacology; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D003891:Desipramine / Q000494:pharmacology; D007488:Iprindole / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D010656:Phenylephrine / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000378:metabolism; D013788:Thalamus / Q000378:metabolism
D000928:Antidepressive Agents; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D000639:Amitriptyline; D010656:Phenylephrine; D007488:Iprindole; D003891:Desipramine; D011224:Prazosin