Abstract: | The immediate effect of cigarette-smoking on ADP-induced platelet aggregation and on platelet adhesiveness was investigated in 12 normal subjects aged 20 to 40, in 10 normal subjects aged 43 to 72 and in 10 patients with cerebrovascular disease aged 45 to 75. All the subjects were heavy smokers (more than 20 cigarettes a day). After smoking 2 cigarettes a significant increase in ADP aggregation and platelet adhesiveness was found in the group of young heavy smokers, while in the old subjects with or without cerebrovascular disease the increase in platelet activity was never significant. These data were discussed and some hypotheses for this higher reactivity of platelets from young people were suggested. |