Chronic treatment with citalopram does not affect the expression of alpha1-adrenergic receptor (alpha1-AR) subtypes.

Abstract

We previously reported that chronic treatment with imipramine and electroconvulsive shock up-regulate the density and alpha1A-adrenergic receptor (alpha1A-AR) mRNA level in the rat prefrontal cortex, while the expression of the alpha1B subtype was unchanged. The present study examined whether repeatedly given citalopram, a selective serotonin reuptake inhibitor, induces any changes in the expression of alpha1A and alpha1B subtypes of alpha1-AR. The receptors density was assessed in the rat cerebral cortex by [3H]prazosin binding while the expression of alpha1A and alpha1B receptors' mRNA was measured in the rat prefrontal cortex by Northern blot analysis or competitive reverse transcription and polymerase chain reaction (RT-PCR), respectively. We did not find any changes in alpha1A- and alpha1B-AR density or mRNA expression in the investigated rat brain structures of citalopram-treated rats. Thus, it seems that up-regulation of alpha1A-AR subtype is characteristic only of those antidepressant agents in which a noradrenergic component is involved in their pharmacological mechanism of action.