REGIONAL EXPRESSION OF C-FOS IN RAT-BRAIN FOLLOWING STIMULATION OF THE VENTRAL TEGMENTAL AREA

This study has investigated the effect of stimulating the region of or igin of the mesolimbic dopaminergic system, the ventral tegmental area (VTA), with the substance P analogue DiMe-C7 on the regional expressi on of c-fos in the rat forebrain. We have previously shown this treatm ent produced a prolonged increase in blood pressure and heart rate whi ch was mediated by both dopaminergic mechanisms and vasopressin releas e. Stimulation of the VTA resulted in increased levels of c-Fos immuno staining in several target regions of the mesolimbic dopaminergic syst em (such as the frontal cortex, olfactory tubercle, islands of Calleja and amygdala), with the notable exception of the nucleus accumbens. A marked increase in c-fos expression was also found in the supraoptic nucleus but not the paraventricular nucleus in the hypothalamus. These results support a role for a number of target areas of the mesolimbic dopaminergic system and vasopressin release in the increase in blood pressure and heart rate produced by stimulation of the VTA. Copyright (C) 1996 Elsevier Science Ireland Ltd.