Padronização de métodos para determinação da atividade de colinesterase eritrocitária e plasmática

Abstract

In Brazil, acute poisoning by pesticides occupy the third position among the causative agents behind only drugs and poisonous animals. And of pesticides, insecticides account for the majority of cases, being among them organophosphates and carbamates, which are the enzyme acetylcholinesterase inhibitors. For the diagnosis of acute and chronic poisoning of workers is important to realize the determination of enzyme activity. Thus, the study aims to standardize the methodologies necessary for the determination of cholinesterase erythrocyte and plasm by spectrophotometric and potentiometric methods and perform comparison between the results obtained for both methods. Standardizing the spectrophotometric method based on the colorimetric measurement of the rate of hydrolysis of acetylthiocholine by blood cholinesterases, and potentiometric method which relies on the measurement of pH change in a medium to which is added the sample was performed (plasm or solution erythrocytes), which will be measured enzyme activity, and substrate (acetylcholine) in buffered medium. For this standardization simulated samples were no inhibition (control) and samples with inhibition 1 hour and 24 hours, using an organophosphate insecticide malathion, added to plasm and blood. As a result it was observed that the amount of cholinesterase no inhibition was higher than in samples where there was inhibition, and furthermore, the spectrophotometric method was able to establish a larger difference in the result of enzymatic activity when analyzed samples inhibited by 24 hours when comparing to the potentiometric method.