Soukup_2008_Neuro.Endocrinol.Lett_29_759

OBJECTIVES: The current standard treatment of organophosphate poisoning consists of an administration of anticholinergic drugs and cholinesterase reactivators (oximes). Oximes can react - except their reactivating effect on cholinesterases - directly with cholinoreceptors. HI-6 is an oxime that may have an inhibitory effect on the muscarinic receptors, too. METHODS: In our work, we have investigated an influence of HI-6 on the acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and on the muscarinic receptors in vitro. The study was conducted using biosensor technique and on the rat bladder using in vitro test (tissue bath; methacholine as muscarinic agonist). IC50 for BChE from human serum was determined to be 1.01x10-6 M and for human erythrocytes AChE 3.31x10-6 M, respectively. CONCLUSION: We assume that the demonstrated contractile response can be attributed to the inhibition of the AChE at the lower concentration and to a predominant inhibition of muscarinic receptor at higher concentration of compound tested.