Prostaglandin metabolism in experimental cerebral vasospasm

Experimental cerebral vasospasm was produced in the canine basilar artery by an intracisternal injection of fresh autogenous arterial blood, and prostaglandins generated in spastic and nonspastic arteries were assessed by thin-layer chromatography. Prostaglandins synthesized in normal arteries were 6-keto-prostaglandin (PG)F1 alpha, PGF2 alpha, PGE2, and PGD2; 6-keto-PGF1 alpha was the most abundant prostaglandin. The study of platelet aggregation suggested that prostacyclin (PGI2)-like activity was manufactured by the normal basilar artery. At 5 minutes after the intracisternal blood injection, no significant changes were evident in syntheses of prostaglandins generated by spastic artery. However, PGE2 synthesis was significantly increased in spastic artery 2 days after the intracisternal blood injection, and 6-keto-PGF1 alpha and PGF2 alpha synthesis and PGE2 synthesis were significantly decreased and increased, respectively, in spastic artery 6 days after the intracisternal blood injection. No significant changes were found in syntheses of 6-keto-PGF1 alpha, PGF2 alpha, and PGE2 manufactured by nonspastic arteries at any stage. Formation of thromboxane B2 was not detected in normal, spastic, or nonspastic arteries.