Rat platelet aggregation: strain and stock variations

Platelet aggregation induced by ADP, arachidonic acid, and collagen was monitored in rats from two stocks, WSU-SD and CD, and from three strains, Lewis, Holtzman, and NBR. ADP-induced aggregation did not vary between the WSU-SD, CD, Lewis, Holtzman, and NBR rats. In contrast, the response to AA and collagen depended upon the stock or strain of rat. Platelets from the Holtzman and especially the NBR were much more sensitive to AA than were those from the other strains. At 0.25 mM AA, 7 of 8 NBR rats and 5 of 8 Holtzman rats aggregated irreversibly, while only 1 in 8 WSU-SD, CD, and Lewis rats aggregated irreversibly at that concentration. Collagen-induced aggregation reflected that to AA. The possible relationship between the variation in platelet aggregation and sympathoadrenal activity is discussed.