ADRENERGIC AND SEROTONERGIC RECEPTOR-BINDING IN RAT-BRAIN AFTER CHRONIC DESMETHYLIMIPRAMINE TREATMENT

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 209  (2) , 256-261
Abstract
The effects of chronic administration of the tricyclic antidepressant agent desmethylimipramine (DMI) on brain adrenergic and serotonergic receptor binding processes were studied. The kinetic properties of .alpha.-adrenergic, .beta.-adrenergic and serotonergic receptor binding sites were examined in cortical and subcortical brain regions of rats treated chronically for various time periods with DMI (6 mg/kg i.p. daily). After 1 wk of daily injections, .beta.-receptor binding density in the cortex was significantly decreased. The reduced density of the cortical .beta.-receptors was evident throughout a 12-wk administration period. It was not until after 6 wk of DMI administration that a significant reduction in the subcortical .beta.-receptors was evident. Compared to saline-injected controls, chronic DMI administration lowered [3H]dihydroalprenolol binding in the hippocampus but not in the striatum. After 12 wk of DMI we detected no differences in .alpha.-adrenergic binding characteristics in the cortex or subcortical forebrain using [3H]dihydroergocryptine as the binding ligand. There was no consistent alteration in the cortical serotonin receptor densities throughout the 12 wk of DMI administration, and DMI had no effect on the serotonergic binding characteristics in the subcortical forebrain region. Apparently, chronic DMI administration selectively decreases the density of .beta.-adrenergic receptors in rat brain.