Effects of NO on the thrombin-induced changes in platelet resistive-volume and platelet morphology. Aspirin-treated and gel-filtered human platelets in the presence of CP/CPK were stimulated with thrombin (0.01 U/mL; heavy blocks) and NO (1.1×10^-10 mol NO/mL/min; narrow bars), as indicated by their respective boxes. Aliquots for resistive-volume measurement and assessment of platelet morphology were withdrawn at the end of each experiment (see “Materials and methods”). ControlAindicates platelets at beginning of the experiments (30 minutes at 37°C after gel-filtration and then stirred for 1 minute). The treatments or sampling conditions are consistent with those indicated by letters i-vi in Figure 1. Results are mean values of 4 separate experiments ± SEM. ^*P < .05 versus control A; †P < .05 versus treatments in E and F.