Antidepressants given repeatedly increase the alpha 1-adrenoceptor agonist affinity in the rat brain.
Several different antidepressant drugs (AD): imipramine, amitriptyline, citalopram and mianserin were administered to rats at a dose of 10 mg/kg po, twice daily for 14 days. The competition studies showed that AD used enhanced the ability of alpha 1-agonist phenylephrine to inhibit the binding of [3H]-prazosin to its receptors (Ki values being decreased) in the cerebral cortex, thalamus and hippocampus. The present results show that the increase in the affinity of alpha 1-adrenoceptors for their agonist is responsible for the functional alpha 1-adrenergic hypersensitivity found after repeated treatment with different AD.
Institute of Pharmacology, Polish Academy of Sciences, Kraków.
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V
Klimek
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Zak-Knapik
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Maj
D000316:Adrenergic alpha-Agonists / Q000378:metabolism*; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D010656:Phenylephrine / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D000316:Adrenergic alpha-Agonists; D000928:Antidepressive Agents; D010656:Phenylephrine; D011224:Prazosin