TRIPLE EFFECT INDUCED BY DELTA-9-TETRAHYDROCANNABINOL ON THE RAT-BLOOD PRESSURE

The intracenous injection of Δ9-trans-tetrahydrocannobinol (2-10 mg/kg) produced dose-related changes in the rat blood pressure. Three efefcts were detected: )1) an immediate and short-lasting hypotension related to brady-cardia, blocked after atropine, vagotomy hexamethonium an dpitching; (2) A rise in blood pressure 30 seconds after injection, insective to yohimbine, hexamethonium, pithing and reserpine treatment; (3) a slow and persistent hypotension, 5 min later, insensitive to atropine and vagotomy but inhibited by hexamethonium, pithing and reserpine treatment. It was concluded that intravenous injection of THC in rats may induced vagal stimualtion and hypptension. This effect was reversed and followed by hypertension due to direct vasoconstriction not dependent on sympathetic activity. After this action a centyral decrease in sympathetic tonus led to a persistent hypotension an effect which is commonly reeported for mammals. © 1979.