Hypotensive and vasodilatory activity of (+/-) 1-o-octadecyl-2-acetyl glyceryl-3-phosphorylcholine in the normotensive rat

Synthetic (+/-) 1-O-octadecyl-2-acetyl-glyceryl-3-phosphorylcholine (octadecyl-AGPC) in microgram/kg doses given intravenously effectively and potently lowered mean arterial blood pressure in conscious and anesthetized normotensive rats. The hypotensive activity was much more pronounced in the anesthetized rat than in the conscious rat. The hypotension was associated with a significant elevation in plasma renin activity (PRA). In the rat in which the hindquarters were perfused, octadecyl-AGPC given intraarterially effectively decreased the perfusion and systemic pressures in a dose-dependent manner. Pharmacological blockade with specific cholinergic, histaminergic or beta-adrenergic receptor antagonists, did not block or attenuate the octadecyl-AGPC-induced reduction in perfusion or systemic pressure. These results suggest that the hypotensive activity of octadecyl-AGPC in the normotensive rat is the result of direct vasodilation and not the result of cholinergic, histaminergic or beta-adrenergic receptor interaction.