Fig. 5. Inositol 1,4,5-triphosphate (IP3) formation in platelets induced by (+)-9,11-epithia-11,12-methano-thromboxane A2(STA2; 0.5 μm) and thrombin (0.02 U/ml). Ketamine (1 mm) suppressed IP3formation induced by STA2and thrombin (n = 5 each). Data are expressed as mean ± SD. *P < 0.05 versus control group.