Effects of dopaminergic compounds on carbonic anhydrase isozymes I, II, and VI

Studies on carbonic anhydrase (CA, EC 4.2.1.1) inhibitors have increased due to several therapeutic applications while there are few investigations on activators. Here we investigated CA inhibitory and activatory capacities of a series of dopaminergic compounds on human carbonic anhydrase (hCA) isozymes I, II, and VI. 2-Amino-1,2,3,4-tetrahydronaphthalene-6,7-diol hydrobromide and 2-amino-1,2,3,4-tetrahydronaphthalene-5,6-diol hydrobromide were found to show effective inhibitory action on hCA I and II whereas 2-amino-5,6-dibromoindan hydrobromide and 2-amino-5-bromoindan hydrobromide exhibited only moderate inhibition against both isoforms, being more effective inhibitors of hCA VI. K-i values of the molecules 3-6 were in the range of 41.12-363 mu M against hCA I, of 0.381-470 mu M against hCA II and of 0.578-1.152 mu M against hCA VI, respectively. Compound 7 behaved as a CA activator with K-A values of 27.3 mu M against hCA I, of 18.4 mu M against hCA II and of 8.73 mu M against hCA VI, respectively.