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67 Cards in this Set
- Front
- Back
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What do organophosphorus esters inhibit?
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Acetylcholinesterase
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Are phosphates active or inactive toxicants?
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active - that inhibit AchE
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What are phosphorothioates?
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protoxicants
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What characteristic of OP make it able to be absorbed by inhalation and dermal contact?
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it is lipophilic
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Are OP long lasting in the environment? Why?
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no - they are esters therefore hydrolyzed easily
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What are OP used for?
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-contact insecticides (malathion and chlorpyrfos)
-systemic insecticides -chemical warfare -industrial chemicals (plastics, lubricants) |
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OPs cause overstimulation of what?
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muscarinic sites and the PNS
-nicotinic sites CNS receptors |
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What is "aging" when referring to OPs?
-when does this occur? |
when OPs bind to esteratic sites of AChE irreversibly (covalent bonds)
-expected in less than 60 minutes |
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What about RBCs is valuable for diagnosis?
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true AChE is in mammalian RBCs therefore can be measured
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What are the acute PSN, muscarinic clinical signs of OP poisoning?
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-act on heart, GI and salivations
SLUD S=increased salivation L=increased lacrimation U=increased urination D=increased defecation (peristalsis) -decreased HR -decreased pupil size -lack of response to pre-anesthetic dose of atropine |
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Do all animals show all the signs for OP poisoning?
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no
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What are the acute nicotinic receptor signs of OP poisoning?
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tremors
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What are the acute CNS signs of OP poisoning?
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stimulation then block
-excitement then depression |
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What is the threshold for signs with OP poisoning?
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<50% of AchE in RBCs
<30% of normal AchE in brain -signs may last 1-5 days |
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What is the cause of death with OP poisoning?
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resp. failure
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What type of signs does atropine help with when treating OP poisoning?
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muscarininc signs only
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How do you administer atropine with OP poisoning?
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1/4 IV
3/4 SC |
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What is used to regenerate AcHE at the muscarinic and nicotinic sites after OP poisoning?
-when is it given? |
pralidoxime - 2-PAM
-given BEFORE aging |
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If you didn't give 2-PAM after OP poisoning, how long would it take to regenerate AChE?
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1-5%/day
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What is the treatment for intermediate syndrome OP poisoning?
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wait and watch
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Delayed effects of OPs occur with what type?
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NTE inhibitors
-neurotoxic esterase |
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What can NTE inhibition predict?
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if OPIDN will occur
(organophosphate delayed neuropathy) |
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Is NTE related to AchE inhibition?
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no
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Intermediate Syndrome of OP includes what?
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a nicotinic effect at the NMJ that reverses with time
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How long does it take for NTE inhibition to occur?
OPIDN? |
-NTE inhibition - hours
-OPIDN - weeks |
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Activated protoxicants are inactivated by what?
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-type A enzymes - not inhibited by OP (BIRDS lack these)
-type B enzymes (AChE, pChe, CbxE) --> ARE inhibited by OP |
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Are young more or less susceptible to inhibition of AChE or OPIDN?
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-more susc. to inhibition of AChE
-less susc. to OPIDN |
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Are Carbamates more readily or less readily absorbed from the skin than OP?
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less - less lipophilic
-more polar |
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Is the binding of carbamate to AChE reversible?
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yes
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Is there aging with Carbamate poisoning?
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no
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Is 2-PAM needed for Carbamate poisoning?
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no - time is best
treatment is atropine + time |
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What action do neonicotinoids have?
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agonist then antagonist at nicotinic sites (and autonomic ganglia)
-stimulate then block, esp at NMJs |
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What is the treatment for nicotine poisoning?
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-artificial respiration
-possible use of a ganglionic blocker (macylamine) |
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What is the prognosis for nicotine poisoning?
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poor
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What is imidacloprid and what is it normally used for?
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-neonicotinoid
-crop protection from sucking, but not chewing insects and a topical flea adulticide for dogs and cats |
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What occurs with neonicotinoid poisoning and what is the antidote?
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-stimulates than blocks nicotinic receptors
-there is no antidote but recovery is usually in 12-24 hours without sequele |
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Ion channel insecticides target what?
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Na channels - keep them open
Cl channels - GABA (inhibitory NT) has a Cl channel and can be blocked |
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What type of general symptoms does ion channel insecticides cause?
how are these treated? |
stimulation of the NS (excitement)
-convulsions -treated with time and removal from exposure, but general treatment is symptomatic (treat with GABA agonist anticonvulsants) |
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What mechanism does Fipronil inhibit?
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GABA antagonist
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Is fipronil readily absorbed from the skin and if it does get in the body, what happens to it?
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-no
-if enters body, undergoes enterohepatic circulation |
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What is the action of pyrethrins and pyrethroids?
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act on Na channels
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Are pyrethrins/oids polar or non-polar?
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polar
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What animals are the most sensitive to pyrethrins/oids?
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cats, birds, fish because metabolized by esterases and mixed function oxidases (also glucuronidation)
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T syndrome from Type I pyrethroids show what type of signs?
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tremors and excitation
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CNS syndrome from Type II pyrethroids show what type of signs?
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tonic/clonic seizures
- have a CN group (fenvalerate) |
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What is the treatment for pyrethrins/pyrethorid exposure?
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wash
-treat symptoms (anticonvulsants) -good prognosis |
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What type of compound is DDT?
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organochlorine - chlorinated hydrocarbon
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Do OC cause more acute or chronic signs and how do they work?
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chronic
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How do the multicyclic OC work?
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they are GABA receptor antagonists
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How do the aliphatic OC work?
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prevent closing of Na channels
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Are OC lipophilic?
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yes therefore absorbed by all routes and distributed to all tissues
-stored in fat and gets into milk |
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What does it mean when OC biomagnify?
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conc. in animal bodies increases as you get up the food chain
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Are acute toxicities common with OCs?
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no b/c may take <14 days after exposure to appear
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What is the mechanism of action for chronic toxicities with OCs?
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induction of microsomal enzymes that leads to reduction of steroid hormones (esp. androgens); this can occur with a single exposure because OCs stay in the body
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What is amitraz normally used for?
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mites, ticks, as a topical vet drug combined with semicarbazone, Na channel blocker for dogs and crops (catapillers)
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What is the mechanism of action of amitraz?
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alpha 2 agonist --> sedation
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What is the treatment for amitraz toxicity?
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alpha -2 antagonist
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What is hydramethylnon used for?
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stomach poison for fire ants
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What are the symptoms of hydramethylnon poisoning and what is the treatment?
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-increased salivation, tremors, GI
-treatment is symptomatic |
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What is boric acid used for?
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to control ants and roaches
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What are the symptoms of boric acid poisoning?
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GI signs, kidney damage
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Is activated charcol useful with boric acid?
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no
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How does DEET work?
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decreases ability of insect to detect warmth and moisture
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What is the mechanism of action of lufenuron?
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interferes with chitin
-lipophilic and concentrates in milk |
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What is methoprene used for?
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flies
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What is rotenone used for and what is the most common adverse side effect?
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topical for lice and mites, fish anesthetic
- dermal irritation |
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What are some negatives about using biological controls?
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-introduce another species
-control agents often have limited spectrum |
