CHANGES IN RAT ADRENAL MEDULLA FOLLOWING Δ9-TETRAHYDROCANNABINOL TREATMENT. A HISTOCHEMICAL STUDY

Abstract

ABSTRACT The effects of acute (10 mg/kg) and chronic (10 mg/kg for 30 days) administration of delta-9-tetrahydrocannabinol (Δ9-THC) have been studied histochemically in the rat adrenal medulla, which include total catecholamines, noradrenaline, histometric measurements of adrenal medullary areas, calcium content of the medullary cells along with adenosine triphosphatase (ATPase), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) activities. Acute Δ9-THC treatment reduced the total catecholamine content (including noradrenaline) of the gland, was accompanied by increased ATPase, AChE, BChE activities and increased calcium distribution in the gland. Chronic Δ9-THC treatment caused significant hypertrophy of the chromaffin tissue, with decreased total catecholamine content, although noradrenaline containing areas exhibited no notable change. The calcium content and ATPase activity were increased along with a concomitant increase in AChE and BChE activities. Although the changes in adrenal medullary enzyme activities following both acute and chronic Δ9-THC treatment are qualitatively similar, marked quantitative increase is noted in the chronically treated groups. The results indicate an increased total catecholamine releasing activity of the adrenal medulla following acute Δ9-THC treatment, while chronic Δ9-THC administration produces a preferential release of adrenaline.