Organochlorines Flashcards
Sources of OC poisoning
ingestion of contaminated feeds, sprayed foliage or pesticide containers
may be absorbed through skin, MM, inhaled
Properties of OC
highly lipophilic, soluble in oils and organic solvents
persistent in environment bc resist chemical or microbial decompositions
Which animals are most sensitive to OC toxicity? A) horses B) dogs C) cats D) cows
C - cats
Toxicokinetics of OC?
after absorption, insecticide may be bound to serum lipoproteins
distributed to body tissues, mainly fat
metabolized by liver microsomal enzymes
T/F: OC undergo enterohepatic recycling
True
MoA of organochlorines
diphenul aliphatics interfere with Na channels in nerve membranes causing repetitive firing and CNS stim and siures
Lindane may inhibit GABA binding
inhibition of cerebral cortex
Clinical signs of organochlorine toxicity?
CNS hyperstimulaton - salivation, nausea, vomiting, tremors, hyperthermia, incoordination, opisthotonos, clonic-tonic seizures
cattle - backwards walking and abnormal postures
birds - depression, apparent blindness, abnormal postures, death
Lesions associated with OC toxicity
nothing specific
bruising and lacerations from convulsions
congestion and edema in several organs
Treatment of OC toxicity?
no specific tx
decontamination, bathe animal for dermal exposure, symptomatic tx (diazepam or barbiturates to control CNS stim, chloral hydrate in large. animals, artificial respiration with oxygen)
Specific MoA of DDT
Axonal Na channels remain open and K+ channels don’t open completely - repolarization inhibited
continued neurotransmitter release = hyperexcitability of neurons
Specific MoA of chlorinated alicyclics
blocks action of GABA
Cl channels don’t open, inhibition of Cl flow into neurons, inhibits repolarization = hyper excitability of neurons
