CONTRAST-MEDIA ALGOGENIC POTENTIAL IN PERIPHERAL ARTERIOGRAPHY - POTENTIATION OF BRADYKININ-INDUCED PAIN IN THE RAT

RATIONALE AND OBJECTIVES. Contrast media (CM) with minimal algogenic (pain causing) potential in animal models of peripheral arteriography are still able to produce vascular pain in humans; the poor predictive value of preclinical evaluation led us to develop a more sensitive method based on CM potentiation of bradykinin effects in the rat. METHODS. Behavioral pain responses and histologic alterations of the arteries were determined after intrafemoral injection of bradykinin to saline- or CM-pretreated rats. Pain reactions were compared with those elicited by single and repeated CM injections. RESULTS. Contrast media enhanced bradykinin-induced pain was dose dependent with the following potency order: iopamidol > iopromide > ZK 139129 > ZK 119095. Vasodilation and alterations of the arterial internal layer also were seen. Iopromide produced this sensitization at doses that did not elicit evident pain reactions per se. CONCLUSION. The method proved to be a highly sensitive preclinical discriminant of CM algogenic potential.