Induction of new carbonic anhydrase II following treatment with acetazolamide in DBA and C57 mice.
The mechanism by which animals develop tolerance to the antiepileptic effects of the carbonic anhydrase (CA) inhibitor, acetazolamide, was explored using a quantitative immunocytochemical method. Cerebral cortex sections of DBA/2J mice susceptible to audiogenic seizures and of C57BL/6J nonsusceptible mice were stained with antibody to mouse CA II in controls and following treatment with acetazolamide (40 and 200 mg/kg) for 1, 3, and 5 days. The percentage increases in CA II fluorescent intensity of cells from C57 mice treated with 40 and 200 mg/kg acetazolamide over those of untreated mice were 22 and 36%, respectively, after 1 day, 32 and 40%, respectively, after 3 days, and 17 and 40%, respectively, after 5 days of treatment. The corresponding percentage increases in fluorescent intensity of cells from DBA mice over controls were 13 and 32%, respectively, after 1 day, 17 and 41%, respectively, after 3 days, and 26 and 58%, respectively, after 5 days of treatment. The fluorescent intensity of cells from untreated DBA mice was 35% greater than those of untreated C57 mice. In C57 mice the maximum amount of CA II per cell at each dose occurred 24 h after acetazolamide treatment, whereas the amount in DBA mice continued to increase with time and dose up to 5 days. The differences between the two strains can be explained by changes in distribution of CA II to subcellular locations or by defects in phosphorylation of the molecule.
D000086:Acetazolamide / Q000494:pharmacology*; D000818:Animals; D002256:Carbonic Anhydrases / Q000096:biosynthesis*; D002540:Cerebral Cortex / Q000201:enzymology; D004790:Enzyme Induction / Q000187:drug effects; D007527:Isoenzymes / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL / Q000378:metabolism*; D008811:Mice, Inbred DBA / Q000378:metabolism*
D007527:Isoenzymes; D002256:Carbonic Anhydrases; D000086:Acetazolamide