EXPRESSION OF C-FOS IN BRAIN SUBCORTICAL STRUCTURES IN RESPONSE TO NAUSEANT LITHIUM-CHLORIDE AND OSMOTIC-PRESSURE IN RATS

Immunohistochemistry was used to map c-fos expression in rats to inves tigate the neural substrates that mediate the emetic action of lithium chloride and the effect of osmotic pressure. Solutions of 3% lithium chloride or 4.14% saline, isotonic to each other, as well as 0.65% lit hium chloride or 0.9% saline, also isotonic to each other, were admini stered intraperitoneally (3 ml/kg) in rats. Both lithium chloride and osmotic pressure enhanced c-fos expression in the nuclei of the solita ry tract, the paraventricular nuclei and supraoptic nuclei of the hypo thalamus, and in the amygdala. This suggests that these brain structur es might be the sites where the autonomic, neuroendocrine and behavior al responses elicited by lithium chloride and osmotic pressure are int egrated.