EFFECT OF RADIOGRAPHIC CONTRAST-MEDIA ON HISTAMINE-RELEASE FROM HUMANMAST-CELLS AND BASOPHILS

Radiographic contrast media (RCM) cause histamine-dependent allergic-l ike reactions. The direct effects of diatrizoate (high osmolar ionic m onomer), ioxaglate (low osmolar ionic dimer), iopromide (low osmolar n on ionic monomer and iotrolan (iso-osmolar non ionic dimer) at the con centration of 200 mgI ml(-1) (60 min exposure) on the release of hista mine from human basophils, human lune mast cells (HLMC), and human ski n mast cells (HSMC) were investigated. Diatrizoate induced 48 +/- 4% h istamine release in basophils, 15 +/- 3% in HLMC and 25 +/- 6% in HSMC . The remaining RCM were relatively ineffective activators of histamin e release in both HLMC and HSMC (ioxaglate 4 +/- 1% and 4 +/- 1%, iopr omide 5 +/- 1% and 7 +/- 2%, iotrolan 7 +/- 2% and 10 +/- 3%, respecti vely). Both iotrolan and ioxaglate were effective in basophils inducin g 21 +/- 3% and 24 +/- 6% histamine release. respectively, whereas iop romide was relatively ineffective (7 +/- 4%). Diatrizoate induced hist amine release from all three cell types with optimal levels of histami ne release after a 2-4 h incubation although significant levels occurr ed within 15 min. Dose-dependent histamine release from HLMC occurred in all four types of RCM, the largest response (37 +/- 3%) being produ ced by diatrizoate. The effect of osmolality on histamine release was investigated using different concentrations of mannitol solutions (0.2 5, 0.5 and 1 M). Histamine release from HLMC, HSMC and basophils after 90 min exposure to mannitol (1 M) was 24 +/- 2% (p<0.05), 9 +/- 3% (p =0.06) and 49 +/- 1% (p < 0.05), respectively, suggesting that hyperos molality pei sc can induce histamine release from basophils and mast c ells. Diatrizoate-induced histamine release in all three cell types wa s significantly reduced by lowering the temperature to 0 degrees C and partially attenuated by the metabolic inhibitors antimycin A (1 mu M) and 2-deoxyglucose (5 mM), and by the omission of glucose from the bu ffer solution. Diatrizoate-induced histamine release was not dependent on extracellular calcium. These data suggest that diatrizoate induces histamine release at least in part by non-cytotoxic mechanisms.