Platelet function in the dorsal skin fold chamber of the rat

The majority of the preparations described for studying platelet functions in vivo require the administration of anesthetic agents and surgery. Some anesthetic which are frequently used in microvascular research (such as ketamine hydrochloride and pentobarbital) are reported to exert an effect on platelet properties themselves. Using a modified chamber preparation situated in the rat's dorsal skin fold, it is possible to study platelet function in the same rat with or without anesthesia. Thrombus formation is induced in arterioles and venules by argon-laser irradiation with a local capacity of 25mW and an exposure time of 1/30 s. Platelet function was studied for ten successive days in the same group of rats to examine the model's aptitude for long-term investigations. There was no significant alteration in platelet response during the experimental period. To evaluate the potential antithrombotic effects of the anesthetics, the animals were studied before and after the application of ketaminehydrochloride (130 mg/kg b.w., pentobarbital (25 mg/kg b.w.), or urethane (1,25 g/kg i.m.). The first two drugs caused significant increase in the number of laser injuries in arterioles and venules, although the effect of pentobarbital was weaker especially in venules. The influence of thrombus formation while using these anesthetics could influence the testing of antithrombotic drugs. Urethane had no effect on laser-induced thrombus formation. Furthermore, special attention was paid to spontaneous and laser-induced vasomotion with respect to thrombus formation.