engleski

Effects of desipramine on regional serotonin synthesis in the rat brain: acute and chronic autoradiographic studies

Various studies have implicated the involvement of noradrenaline(NA) and/or serotonin(5-HT) in the pathogenesis and treatment of depression. The aim of the present study was to investigate the effects of acute and 7 days of administration of desipramine, a NA reuptake inhibitor, on the rate of 5-HT synthesis in the rat brain. The study was done by an autoradiographic method using α -[14C]-methyl-L-tryptophan as a tracer. The acute (10 mg/kg, ip, 2h before iv infusion of the tracer) or 7 days of desipramine (10 mg/kg/day, ip) administration did not affect plasma tryptophan (Trp) concentrations, as compared to control (saline treated) rats. Acute treatment with desipramine decreased the rate of 5-HT synthesis in the brain regions that contain 5-HT cell bodies between 19-28%, and increased the rate of 5-HT synthesis in the majority of areas containing 5-HT terminals between 21-65%. In contrast to the acute treatment, 7 days of desipramine administration increased 5-HT synthesis rates in dorsal raphe(24%), but decreased it in raphe magnus(35%), superior olive (45%), caudate(31%), superior(38%) and inferior (53%)colliculus, and in the auditory cortex(35%). This suggest that the effect of desipramine on 5-HT synthesis rate is time-dependent and differs in the cell bodies and structures containing 5-HT nerve terminals.

α -methyl-L-tryptophan; tracer; antidepressant treatment; serotonin synthesis; rat brain

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