HISTAMINE-RELEASE, COMPLEMENT CONSUMPTION AND MICRO-VASCULAR CHANGES AFTER RADIOGRAPHIC CONTRAST-MEDIA INFUSION IN RABBITS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 92  (4) , 584-594
Abstract
The i.v. injection of RCM [radiographic contrast media] into rabbits produced dose-dependent changes in SAP [systemic arterial pressure], MVP [microvascular pressure (arterioles)], RBCV [red blood cell velocity], and plasma histamine and complement [C] concentrations. After infusion of 8 ml/kg Hypaque-50, SAP dropped from 86 .+-. 3 mm Hg to 50 .+-. 3, MVP from 42 .+-. 2 cm H2O to 26 .+-. 3, and RBCV from 0.98 .+-. 0.11 mm/sec to 0.37 .+-. 0.13. The microvascular changes appeared 10 s after injection and persisted for 10-40 min. During the course of the reaction it was observed that leukocytes adhered to the endothelial walls and red blood cells shrank and finally aggregated in the microvessels. The microvascular changes were accompanied by an increase in plasma histamine concentration, with an average of 44 ng/ml after 2 min, and a drop in total plasma CH50 [C hemclytic titer] by an average of 46%. Infusion of 8 ml/kg hyperosmolar saline solution (4.1 gm/dl or 1324 mOsm[milliosmoles]/l produced initial changes in microvascular parameters which returned to normal within a few seconds. At the same time plasma histamine concentration increased slightly without changes in C. The hyperosmolar properties of RCM may contribute to the initial hemodynamic changes observed after RCM infusion. The prolonged microcirculatory disturbances produced by RCM in rabbits appear to be a direct effect of the chemotoxicity of these compounds. Part of this chemotoxicity might result from initial release of vasoactive mediators such as histamine and activation of the C system.