Figure 2 Cyclooxygenase (COX) and thromboxane prostanoid (TP) receptor mediated endothelium-dependent contractions (EDCs). (A) Original recordings showing acetylcholine (ACh)-induced contractions only in mouse carotid arteries with intact endothelium. (B) ACh-induced concentration-dependent contractions in L-NAME-treated arteries with endothelium (+Endo [n=8] vs. –Endo [n=6]). (C) The inhibitory effects of non-selective COX inhibitor, indomethacin (3 μmol/L, n=6) and the TP receptor antagonist, S18886 (30 nmol/L, n=6) on ACh-induced contraction compared to control (n=5). (D) The effects of COX-1 inhibitor valeryl salicylate (VAS) (30 μmol/L, n=6), COX-2 inhibitor celecoxib (1 μmol/L, n=6), and TP receptor antagonist S18886 (30 nmol/L, n=4) on TP receptor agonist U46619-induced contraction compared to control (n=4). The results are means±standard error of the mean (SEM). * P<0.05 vs. control.