CHRONIC ELECTROCONVULSIVE SHOCK ENHANCES 5-HT2 RECEPTOR-MEDIATED HEADSHAKES BUT NOT BRAIN C-FOS INDUCTION

Chronic electroconvulsive shock (ECS), a widely used treatment for int ractable depression, increases the density of 5-HT2A receptor binding sites and mRNA in rat frontal cortex. In contrast, this treatment appe ars to have no significant effect on 5-HT-stimulated phosphatidyl inos itol turnover in rat brain. To investigate the effect of chronic ECS o n the 5-HT2 receptor family further, we determined its effects on head shakes and c-fos expression in the rat in response to the 5-HT2A/2C r eceptor agonist DOI [1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane]. Chronic ECS (5 electroconvulsive shocks over 10 days, via earclips und er halothane anaesthesia) caused a significant enhancement in the numb er of head shakes counted in a 30 min period after administration of 2 or 8 mg/kg DOI. In contrast, this treatment had no effect on Fos expr ession, induced by either dose of DOI, in any region of rat forebrain examined. Fos expression was low-to-undetectable in the brains of anim als treated with chronic ECS followed by saline and sham ECS animals t hat had been treated identically, but with no administration of electr ocurrent. Thus the lack of any change in PI turnover, following chroni c ECS administration, appears to be mirrored by the failure of this tr eatment to alter 5-HT2 receptor-mediated Fos expression. Copyright (C) 1996 Elsevier Science Ltd.