title: Alterations in autonomic function in the guinea pig eye following exposure to dichlorvos vapor.
abstract: The present study investigated the effect of the organophosphate, dichlorvos (DDVP), on ocular function and cholinesterase activity in guinea pigs, using a single-animal-head-only vapor exposure system. All animals exhibited signs of mild organophosphate poisoning (e.g., salivation, chewing, lacrimation, urination, defecation, and rhinorrhea) after the 20-min exposure, regardless of the DDVP exposure concentration (e.g., 35 mg/m(3), 55 mg/m(3), and 75 mg/m(3)). Pupil constriction or miosis was the most pronounced effect seen after vapor exposure. The postexposure pupil size for the 35 mg/m(3) group was 45.8 +/- 3.68% of the preexposure baseline measurement. Postexposure pupil size in the 55- (38 +/- 1.36%) and 75 mg/m(3) (38.1 +/- 1.72%) groups was significantly less than both the preexposure baseline level and the 35 mg/m(3) group. All groups exhibited enhanced an pupillary response to light after DDVP exposure. The enhanced light response remained even after recovery from miosis (approximately 1 h after exposure). Measurement of cholinesterase activity revealed that even though pupil size had recovered, acetyl- and butyrylcholinesterase remained significantly inhibited in the blood.
authors.affiliation: US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010-5424, USA. james.tracy.taylor@us.army.mil
authors.forename: James T
authors.initials: JT
authors.lastname: Taylor
authors.forename: Emily
authors.initials: E
authors.lastname: Davis
authors.forename: Paul
authors.initials: P
authors.lastname: Dabisch
authors.forename: Mike
authors.initials: M
authors.lastname: Horsmon
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Robert
authors.initials: R
authors.lastname: Mioduszewski
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood / Q000378:metabolism; D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects*; D002091:Butyrylcholinesterase / Q000097:blood / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D004006:Dichlorvos / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005123:Eye / Q000187:drug effects* / Q000294:innervation; D006168:Guinea Pigs; D019570:Inhalation Exposure; D008297:Male; D012025:Reflex, Pupillary / Q000187:drug effects; D014835:Volatilization
chemical_list: D002800:Cholinesterase Inhibitors; D004006:Dichlorvos; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase