Adenosine release in morphine-induced hypotension in rats

Abstract

1. 1. Following intravenous administration of morphine.HCl a reduction in mean arterial blood pressure (MABP) was produced, quaternary morphine analogue was ineffective. 2. 2. Theophylline and 8-phenyltheophylline administration reduced morphine-induced hypotension. 3. 3. A 2 adenosine receptor agonist caused an hypotension while A 1 adenosine receptor agonist was ineffective. 4. 4. l -N G -Mono-methylarginine administration reduced the hypotensive effect of exogenous A 2 agonist while it was ineffective on morphine-induced hypotension. 5. 5. Morphine-induced hypotension was increased by pretreatment with dipyridamole, whereas tetrabenazine abolished it. 6. 6. The present study is consistent with previous reports on the central hypotensive action of morphine and propose a role for adenosine release in morphine-induced hypotension.