Clinical manifestations and leukocyte neurotoxic esterase and red blood cell and plasma acetylcholinesterase activities in swine following a single oral dose of tri-o-cresyl phosphate.
We report the clinical signs and the effects on leukocyte neurotoxic esterase and red blood cell and plasma acetylcholinesterase (AChE) activities in swine orally administered a single dose of tri-o-cresyl phosphate (TOCP) at 400, 800 or 1000 mg/kg. Swine in all dosage groups exhibited signs consistent with inhibition of nervous tissue cholinesterase 3-48 h after TOCP administration. Onset was dose-related, and 2/3 1000 mg/kg dosed swine died 3 or 35 h postdosing. In surviving swine, significant depressions in plasma AChE activity were apparent at 6 h postdosing, ranging from 16-23% of predosing levels. Similar depressions of red blood cell AChE were not observed until 24 h postdosing. Plasma AChE activities appeared to more accurately reflect the development of acute cholinergic signs observed in the 1000 mg/kg dosed swine at 3 h postdosing while red blood cell AChE activities were more consistent with the delayed cholinergic signs exhibited by the 400 and 800 mg/kg dosed swine at 24 h postdosing. All survivors developed signs of delayed neurotoxicity 10-12 d after TOCP administration, and 70% or greater inhibition of neurotoxic esterase activity in leukocytes was apparent during the first 48 h postdosing.
Barrett
D S
DS
College of Veterinary Medicine, Kansas State University, Manhattan 66506.
Oehme
F W
FW
Kruckenberg
S M
SM
Smith
J E
JE
D000110:Acetylcholinesterase / Q000097:blood*; D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D005260:Female; D007962:Leukocytes / Q000187:drug effects / Q000201:enzymology; D008297:Male; D010949:Plasma / Q000187:drug effects / Q000201:enzymology; D013552:Swine; D014317:Tritolyl Phosphates / Q000008:administration & dosage / Q000633:toxicity*
D014317:Tritolyl Phosphates; D002265:Carboxylic Ester Hydrolases; C021859:neurotoxic esterase; D000110:Acetylcholinesterase; C025541:tri-o-cresyl phosphate