Experimental study of argon laser-induced microthrombosis during PGI2 infusion

In order to evaluate the Argon laser-induced microthrombogenesis during prostacyclin (PGI2) infusion on newly formed microcirculation in the rabbit ear chamber, time-space parameters have been calculated in 118 observations subdivided into 4 groups according to the type and size of the vessels irradiated. The observations were carried out without drug treatment, with continuous infusion of pH 10.5 glycine buffer and with continuous infusion of PGI2 at the dosage of 125 ng X kg-1 X min-1 diluted in the glycine buffer. The results indicated that during PGI2 infusion the size of the thrombus, measured by maximal thrombus area, was always significantly less extended than in untreated animals. Moreover, the number of emboli detached during the first 5 min after laser exposure, measured by rate of embolization, during PGI2 infusion in venules and in the larger arterioles was smaller than in untreated animals. The vasoconstriction which usually takes place in the arteriolar vessels--upstream and downstream from the irradiated site--was in no way modified by the infusion of PGI2. Finally, it was noted that glycine buffer infusion showed an unforeseen activity on laser-induced vascular reactivity.