2,3-dinor-8-iso Prostaglandin F1α (2,3-dinor-8-iso PGF1α) is an isoprostane and active metabolite of arachidonic acid and the platelet aggregation inhibitor 8-iso PGF2α .^1,2 It is formed by the non-enzymatic, free radical peroxidation of arachidonic acid.¹ 2,3-dinor-8-iso PGF1α induces vasoconstriction in isolated porcine retinal and brain microvessels (EC50s = 12.8 and 18.5 nM, respectively) but does not induce contraction of isolated rat aortic rings when used at a concentration of 31 µM.^1,3 It increases thromboxane B2 (TXB2) levels in isolated porcine brain slices when used at a concentration of 1 µM, an effect that can be reversed by the thromboxane A synthase inhibitor CGS 12970, the voltage-gated calcium channel inhibitor SKF 96365 , or nicotinic acetylcholine receptor (nAChR) antagonist α-conotoxin.¹