DEXAMETHASONE TARGET SITES IN THE CENTRAL-NERVOUS-SYSTEM AND THEIR POTENTIAL RELEVANCE TO MENTAL-ILLNESS

1. The topical distribution of tritiated dexamethasone (DEX), a potent synthetic glucocorticoid of widespread use in the diagnosis and assessment of mental illness, was studied in rat CNS by autoradiography to obtain information on potential traget sites for feedback and other centrally mediated effects of glucocorticoids. 2. The cells of the arcuate nucleus of the hypothalamus and the lateral thalamic nuclei displayed the most concentrated nuclear accumulation of silver grains. 3. Significant accumulation, exceeding that found in the hippocampal formation, also occurred in the cells of the ventromedial, periventricular, and paraventricular nuclei of the hypothalamus, the locus ceruleus, the nucleus tractus solitarii, and the area postrema, none of which are targeted by corticosterone, the native glucocorticoid of the rat. 4. Nuclear accumulation of silver grains was prominent in neural and glial cells of the cerebral cortex, the olfactory nucleus, the dorsolateral septum, the amygdala, the subfornical organ, the lateral parabrachial, medial trapezoid, and dorsal reticular nuclei, the nucleus centralis of the raphe, the cerebellum, and vascular tissues.