Desensitization of beta-adrenoceptors following repeated injections of 2-substituted 4-phenylquinolines.
The chronic effects of five 2-substituted 4-phenylquinoline derivatives on the sensitivity of the noradrenergic cyclic AMP-generating system in the rat brain cortex have been determined, and compared with those of the typical and atypical antidepressants imipramine and trazodone, respectively. Acute treatment (single i.p. dose of 20 mg kg-1) and sub-chronic treatment (20 mg kg-1 daily for 10 days) induced no significant desensitization of the beta-adrenoceptors. However, chronic treatment (20 mg kg-1 daily for 3 weeks) significantly decreased the isoprenaline-induced increase in cyclic AMP, suggesting desensitization. This effect, coupled with previous findings, points to a potential role of these compounds as antidepressants.