Studies on Mechanisms of the Toxic Effects of Cadmium in Mouse Tracheal Organ Culture

Abstract

Exposure of tracheal organ cultures to 10μM cadmium acetate resulted in a reduction of ciliary activity by 89% and a profound swelling of the epithelial cells within 4 hours. Substances with specific effects on ion transport systems did not interact with these cadmium induced effects. The swelling took place without any significant alterations of the intracellular electrolyte content (Na⁺, K⁺). Trifluoperazine (0.1mM), a calmodulin-specific drug, resulted in a reduction of ciliary activity similar to that induced by 10μM cadmium acetate, and induced a prominent swelling in part of the epithelial cell layer. A possible mechanism for the toxicity of cadmium could thus be binding of Cd²⁺ to the Ca²⁺ sites on calmodulin, causing dysfunctions of its normal regulatory role in both ciliary activity and volume control.