Erowid References Database
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Tang SW, Seeman P.
“Effect of Antidepressant Drugs on Serotonergic and Adrenergic Receptors”.
Naunyn-Schmiedeberg's Arch. Pharmacol.. 1980;311(3):255-61.
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Abstract
The effect of antidepressant drugs on serotonergic and adreneraic receptors was studied in the calf brain. Calf frontal and cerebellar homogenates were used in the binding sites. 3H-WB-4101 (New ngland Nuclear) was used to label post synaptic alpha1 receptors. 3H-Clonidine (Boehringer Ingelheim), was used to label post synaptic alpha2 receptors. 3H-Dihydroalprenolol (3H-DHA; New England Nuclear) was used to label beta1 receptors in calf frontal cortex and beta2 receptors in calf cerebellar cortex. 3H-5HT (New England Nuclear) and 3H-LSD (New England Nuclear), in the presence of 100 nM phentolamine, were used to label Serotonergic receptors. The following antidepressant drugs were tested for their competitive binding to the radio-ligands: mianserin HCl (Organon) protriptyline HCl, amitriptyline HCl (Merck-Sharp and Dohme), clomipramine HCl, maprotiline HCl, imipramine HCl, desipramine HCl (CIBA-Geigy), doxapin HCl (Pfizer), trimipramine maleate (Poulenc), nortriptyline HCl (Eli Lilly), iprindol (Wyeth), nomifensine (Hoechst) and zimelidine (cis form; Astra Chemicals). Significant potency was displayed by mianserin and some tertiary tricyclic antidepressants in inhibiting 3H-WB-4101 binding in the calf frontal cortex. The most potent drugs were doxepin, amitriptyline, mianserin and trimipramine, whilst the least potent were nomifensine, iprindole and zimelidine. Mianserin was the only drug which significantly displaced 3H-clonidine binding (IC5o = 12 nM). None of the drugs were potent at inhibiting 3H-DHA binding either in calf frontal cortex or cerebellum. Several of the antidepressants showed weak, but significant, inhibition of the binding of 3H-LSD and 3H-5HT. Only mianserin, doxopin and amitriptyline had low IC50 values. The secondary amine tricyclics were not very potent inhibitors of the binding of the radioligands, whereas most of the tertiary amine tricyclics were inhibitory at levels which occur clinically in plasma water. The differences between the effects of the antidepressants on adrenergic and serotonergic receptors may be responsible for the differences in their therapeutic effiacies and side effects.
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