MECHANISMS OF THE ACTION OF NA-NITROPRUSSIDE AND SOME CYANIDES ON CHOLINESTERASES IN INVERTEBRATES AND VERTEBRATES ANIMALS
ELITZA T. DENCHEVA1*, RADOY I. IVANOV2
1 Sofia University “St. Kliment Ohridski”, Faculty of Biology, Department of Zoology and Anthropology
2 Sofia University “St. Kliment Ohridski”, Faculty of Biology, Department of Human and Animal Physiology, Sofia, Bulgaria
*Corresponding author: e-mail: elidencheva@abv.bg
Keywords: Acetylcholinesterase (AChE); butyrilcholinesterase (BChE); Na-Nitroprusside; nitric oxide; L-Arginine; K-ferri- and ferrocyanides
Abstract: This study aims to reveal some mechanisms of the inhibitory effect of Na-Nitroprusside (Na-NP) on cholinesterase (ChE) activity in vertebrate and invertebrate animals. Na-NP is a synthetic exogenous nitric oxide (NO) donor and is a very effective medicine for the treatment of acute hypertension. Overdose, however, may cause intoxication and death. This is one of the reasons that has prompted our attention to its mechanism of intoxication. As we have found in other studies, the effects of Na-NP on cholinesterases are biphasic – moderate activation of enzyme activity at very low concentrations and progressive concentration-dependent inhibition of the enzyme. This inhibitory effect is due to specific metabolic products released during the decomposition of Na-Nitroprusside. This influence largely resembles the effects of anticholinesterase agents. Under these circumstances, the hypotonic efficacy of Na-NP can be explained by vagotonic activity (increased acetylcholine content and blood vessel relaxation). In this work, the influence of various cyanide products has also been traced. It was established for the first time that nitro-ferri-cyanides concentration-dependently inhibit cholinesterase activity in invertebrates and vertebrates. Certain scientific findings may be used for treatment of severe mental illness.