Recovery of Brain Acetylcholinesterase and Plasma Cholinesterase Activities in Quail (Coturnix Coturnix) After Chlorpyriphos Administration and Effect of Pralidoxime Treatment

Abstract

Abstract-Chlorpyriphos (13 mg/kg) was administered to quail (Coturnix coturnix), and the responses of brain acetylcholinesterase (AChE) and plasma cholinesterase (ChE) were studied. Both enzymes responded rapidly, and the maximal inhibition (76.6 and 86.1%, respectively) ocurred 8 h postadministration. Plasma ChE recovered rapidly, and even on day 4, ChE values of quail that had received chlorpyriphos were higher than those of controls. The recovery of brain AChE activity was slower than that of plasma; it reached 59% of controls 2 d after chlorpyriphos administration, then it recovered slowly, and only at day 11 was its level not depressed with respect to controls. This recovery followed the logarithmic pattern Y ϭ a ϩ b(log X), where Y is the AChE activity expressed as the percentage with respect to controls and X is the day after dosing, giving a significant correlation (r ϭ 0.9746, p Ͻ 0.001 when using group means and r ϭ 0.9219, p Ͻ 0.001 when using individual values). No clinical signs or mortality were observed, and histopathological observations in the central nervous system (encephalytic reaction, necrotic Purkinje cells), liver (congestion, vacuolation), and kidney (congestion, nephrosis) were not severe and did not endanger the life of the quail. Sixteen hours after chlorpyriphos administration, some quail were treated with pralidoxime, which significantly reactivated brain AChE but not plasma ChE. However, this effect did not last for the rest of the experiment; because no signs of toxicosis appeared, the experiment was not repeated.

Combined Effect of Short-Term Dehydration and Sublethal Acute Oral Dicrotophos Exposure Confounds the Diagnosis of Anticholinesterase Exposure in Common Quail (Coturnix Coturnix) Using Plasma Cholinesterase Activity

“…The CVs for the plasma parameters revealed a ranking of normal homeostatic ranges from narrowest to broadest being P osm ,Hct, plasma ChE activity. Measures and variability of cholinesterase activities in tissues of our quail were consistent with those observed in this species by Soler-Rodriguez et al (1998), who reported mean (CV) brain and plasma ChE activities of 7.32 (11%) mmol substrate hydrolyzed/min/g wet mass and 0.838 (32%) mmol substrate hydrolyzed/min/ml, respectively.…”

Evaluating Reptile Exposure to Cholinesterase-Inhibiting Agrochemicals by Serum Butyrylcholinesterase Activity

“…Permanent inactivation of ChE or aging is dependent on time after exposure. In vitro and in vivo experiments carried out with avian serum and brain ChEs have demonstrated that reactivation using oximes is dependent on the time since exposure [9,10]. Serum BChE activity of G. galloti previously inhibited by paraoxon or dichlorvos did not recover totally in the presence of 2-PAM (see Fig.…”

“…ticides, respectively [7,8]. Reactivation of phosphorylated ChE activity using 2-PAM has been applied in laboratory and field studies using birds as bioindicators [5,9,10]. In addition to evaluating ChE activity levels, the ChE reactivation technique is well established as an indicator of exposure to anti-ChE pesticides.…”

Evaluating reptile exposure to cholinesterase‐inhibiting agrochemicals by serum butyrylcholinesterase activity

“…Permanent inactivation of ChE or aging is dependent on time after exposure. In vitro and in vivo experiments carried out with avian serum and brain ChEs have demonstrated that reactivation using oximes is dependent on the time since exposure [9,10]. Serum BChE activity of G. galloti previously inhibited by paraoxon or dichlorvos did not recover totally in the presence of 2‐PAM (see Fig.…”

“…Chemical reactivation techniques based on oximes (e.g., pyridine‐2‐aldoxime methochloride [2‐PAM]) and water dilution of samples (i.e., spontaneous reactivation) can be used to discriminate between exposure to OP or CB pesticides, respectively [7,8]. Reactivation of phosphorylated ChE activity using 2‐PAM has been applied in laboratory and field studies using birds as bioindicators [5,9,10]. In addition to evaluating ChE activity levels, the ChE reactivation technique is well established as an indicator of exposure to anti‐ChE pesticides.…”