Reactions to contrast media: testing the CNS hypothesis

Sodium iothalamate was injected intravenously into mice to test the hypothesis that reactions to contrast media are controlled by the central nervous system. Particular emphasis was placed on (a) the effect of the limbic portion of the brain on the hypothalamus and (b) the outflow through the autonomic nervous system. Diazepam and hexamethonium significantly affected the LD50; in addition, in comparison trials with control mice, they markedly decreased the death rate (p < 0.0005). High doses of methylprednisolone sodium succinate, given every 6 hours before the contrast medium, had no effect.