PLASMA SEROTONIN AND PLATELET-AGGREGATION DURING ISCHEMIA-REPERFUSIONIN DOGS - EFFECT OF DIPYRIDAMOLE AND COENZYME Q(10)

Platelet aggregation and plasma serotonin were studied during ischemia -reperfusion of the small intestine in dogs. Blood was withdrawn from the superior mesenteric vein before and 1 h after ischemia, then 5, 30 and 60 min after reperfusion. Dipyridamole (5 mg/kg body weight) and coenzyme Q(10) (CoQ(10); 10 mg/kg body weight) were administered intra venously 5 min before reperfusion, following 1 h ischemia, in order to investigate their effects on platelet function and free serotonin. Is chemia-reperfusion resulted in an increased local free serotonin conce ntration together with an enhanced platelet response to ADP, collagen and arachidonic acid. Administration of dipyridamole and CoQ(10) prior to reperfusion prevented, at least in part, augmented platelet activa tion and serotonin release. It appeared that dipyridamole was more pot ent than CoQ(10). Our results may indicate a possible protective effec t of dipyridamole on enhanced platelet activation during ischemia-repe rfusion in dogs.