title: Inhibition of carbonic anhydrase by nitric oxide.
abstract: The aim of the present study was to follow the effect of nitric oxide (NO) on carbonic anhydrase in vitro and in vivo. The effect of L-arginine (as source of NO), as well as that of its analogue, nitro-G-monomethyl-L-arginine, an inhibitor of NO synthesis on carbonic anhydrase, were also studied. In vitro results showed that L-arginine activates carbonic anhydrase, while N-G-monomethyl-L-arginine does not modify its activity. In vivo, L-arginine and N-G-monomethyl-L-arginine increased carbonic anhydrase activity by 72% and, 160% respectively. Administration of L-arginine, as a source of NO, and of acetazolamide before administration of N-G-monomethyl-L-arginine abolished the activating effect of the analogue on carbonic anhydrase. These results lead to the conclusion that inhibition of NO synthesis by N-G-monomethyl-L-arginine induces increase of carbonic anhydrase activity. The data also suggest that NO biosynthetized from L-arginine inhibits carbonic anhydrase.
authors.affiliation: Romanian Academy, Center for Medical Research and Assistance, Simleu Silvaniei, Salaj.
authors.forename: I
authors.initials: I
authors.lastname: Puscas
authors.forename: M
authors.initials: M
authors.lastname: Coltau
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology*; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009569:Nitric Oxide / Q000494:pharmacology*; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000201:enzymology; D011817:Rabbits; D019323:omega-N-Methylarginine
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D004791:Enzyme Inhibitors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D000086:Acetazolamide