Clonazepam-induced up-regulation of serotonin1 binding sites in frontal cortex of rat.
Chronic administration of the benzodiazepine, clonazepam, increased the number of [3H]5-hydroxytryptamine (5-HT1) binding sites in the frontal cortex of the rat. The increase reflected a change in the maximum density of binding sites (Bmax) with no change in ligand affinity (Kd). Increased binding occurred after continued exposure (10 days) to large (5.0 mg/kg) doses of clonazepam. The changes in [3H]5-HT binding were regional in that they occurred in membranes from the frontal cortex but not the brainstem. The effects were also at least partially selective for 5-HT receptors since the binding of the beta-adrenergic radioligand, [3H]dihydroalprenolol, was not affected by clonazepam. A second benzodiazepine, diazepam, did not affect the binding of [3H]5-HT at doses of 30 mg/kg per day. The latter data suggest that the effects of benzodiazepines on serotonin 5-HT1 receptors are unique to clonazepam.
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D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology*; D002998:Clonazepam / Q000494:pharmacology*; D005625:Frontal Lobe / Q000032:analysis / Q000187:drug effects*; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000032:analysis / Q000187:drug effects*; D012701:Serotonin / Q000032:analysis; D013268:Stimulation, Chemical
D001570:Benzodiazepinones; D011985:Receptors, Serotonin; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D002998:Clonazepam