REPEATED ECS DIFFERENTIALLY AFFECTS RAT-BRAIN 5-HT1A AND 5-HT2A RECEPTOR EXPRESSION

WE investigated the effect of electroconvulsive shock (ECS), administe red five times over 10 days, on 5-HT1A and 5-HT2A receptor mRNA and bi nding site densities in the rat brain using in situ hybridization hist ochemistry and quantitative autoradiography. ECS treatment increased 5 -HT1A receptor mRNA abundance and binding site densities in the dentat e gyrus, but decreased these parameters in the CA3c layer of the hippo campus. No changes in 5-HT1A receptor mRNA and binding sites occurred in other hippocampal subfields, neocortex or raphe nuclei. Repeated EC S was also found to increase 5-HT2A receptor binding site densities in the neocortex and this was accompanied by a non-significant increase in cortical 5-HT2A receptor mRNA abundance. Our study demonstrates tha t in the rat, repeated ECS produces anatomically and molecularly discr ete effects on 5-HT1A and 5-HT2A receptor gene expression. These chang es may be relevant to the therapeutic effect of repeated ECS in depres sion.