Effects of morphine on the rat lymphoid organs and adrenal glands: Resultsof enzyme histochemical and histometric investigations

Effects of morphine on the rat lymphoid tissues and adrenal glands were inv estigated by means of histological, histometrical and enzyme histochemical methods. The experimental animals were treated with 5 mg/kg morphine hydroc hloride at daily intervals for 30 days. Morphine treatment caused severe ly mphoid cell depletion from spleen, thymus and lymph nodes whereas, ileal Pe yer's patches were affected moderately. Both peripheral blood lymphocyte pe rcentage and ANAE-positive lymphocyte frequency in the lymphocyte fraction decreased. The changes in lymphoid organs provide morphological evidence fo r morphine induced immune suppression. Along with these, observation of the thickening of the adrenal cortex and medulla might show that morphine indu ced immuno suppression may occur via increased glucocorticoid secretion.