Fig. 6. The suppressive effects of ketamine on membrane-bound guanosine 5′-triphosphatase activity of platelets stimulated by thrombin (0.02 U/ml) and (+)-9,11-epithia-11,12-methano-thromboxane A²(STA²; 0.5 μm). Ketamine (1 mm) dose dependently suppressed guanosine triphosphate hydrolysis induced by these agonists. Data are expressed as mean ± SD. *P < 0.05 versus  zero-control.