Rapid down-regulation of beta-adrenergic receptors evoked by combined forced swimming test and CGP 37849--a competitive antagonist of NMDA receptors.

ABSTRACT

The influence of CGP 37849, a competitive antagonist of NMDA, receptors and desipramine (DMI) on the density of beta-adrenergic receptors in rats exposed to the forced swimming test was investigated. CGP 37849 (10 mg/kg) and DMI (15 mg/kg), given twice to rats (24 h apart), or the forced swimming test alone failed to alter the density of beta-adrenergic receptors in the rat cortex, as tested using [3H]dihydroalprenolol ([3H]DHA). However, in rats injected with CGP 37849 (10 mg/kg) or DMI (15 mg/kg) and exposed to the forced swimming test, it was found that the density of beta-adrenergic receptors in the cortex was decreased. It was also observed that CGP 37849 used in a dose which decreased the density of beta-adrenergic receptors reduced the immobility time in a manner similar to DMI. It is concluded that CGP 37849 may evoke similar adaptive receptor changes as anti-depressant drugs which-in turn-suggests antidepressant-like properties of CGP 37849.