Iotrol, iodixanol, and 2-deoxy-D-glucose effects on neural tissue CO2 production

In vivo and in vitro experiments have demonstrated that the myelographic agent metrizamide decreases neural tissue glucose metabolism whereas iohexol and iopamidol do not. This study compares the changes in slices of rat hippocampus CO2 production caused by the nonionic dimers iotrol and iodixanol with the effects of metrizamide and 2-deoxy-D-glucose. After 6-hr incubations, 70-mmol/l concentrations of iotrol and iodixanol increased CO2 production by 11 +/- 20% and 31 +/- 35%, respectively, as compared with the artificial CSF control medium. Metrizamide at 70 mmol/l and 2-deoxy-D-glucose at 35 mmol/l decreased CO2 production by 32 +/- 13% and 96 +/- 1%, respectively. The increases in CO2 production with iotrol and iodixanol appear to indicate that these molecules have some effect on cell metabolism. The mechanism for the increase in CO2 production could involve an effect on the glucose metabolic pathway or could be indirect via a mechanism that increases cell energy utilization. These in vitro effects have not been verified with in vivo experiments.