ANTIDEPRESSANTS REVERSE THE OLFACTORY BULBECTOMY-INDUCED DECREASES INSPLENIC PERIPHERAL-TYPE BENZODIAZEPINE RECEPTORS IN RATS

The present study investigated the effects of 21-day administration of clorgyline (1 mg/kg/day), desipramine (10 mg/kg/day) or paroxetine (1 0 mg/kg/day) on peripheral-type benzodiazepine receptors in rat periph eral tissues following bilateral olfactory bulbectomy. Thymus and sple en weights decreased as a result of bulbectomy. Subsequent antidepress ant drug administration had no further effects on the weights of thymu s glands but increased those of spleens. In thymus glands, higher dens ities of peripheral-type benzodiazepine receptors were observed in med ulla than in cortex; no significant variations were observed following bulbectomy or antidepressant drug administration. In spleen, higher d ensities were observed in white pulp than in red pulp. The bulbectomy- induced decreases in binding densities observed in both regions were r eversed following administration of antidepressants. Adrenal periphera l-type benzodiazepine receptors were not altered by bulbectomy or subs equent treatment with clorgyline or desipramine while paroxetine upreg ulated these receptors. No changes in kidney peripheral-type benzodiaz epine receptors were observed. The present study confirms that cell li nes of the rat immune system possess high densities of peripheral-type benzodiazepine receptor binding sites and further support the content ion that, following olfactory bulbectomy, rats may present an antidepr essant-reversible immunitary dysfunction.