Tox.Osweiler. Tremor Inducing Toxicants Flashcards
Bermuda grass (cynodon dactylon)
MOA
Characteristics
Toxic principle not described
No distinguishing lesions; signs include tremors, and stiff legged gait, which exercise may worsen
Dallis grass (Claviceps paspali)
MOA
Characteristics
Sclerotia (fungal growth in the grass ovary) porduces alkaloids similar to lysergic acid
Continuous tremors that lessen at rest and are exacerbated by exercise or excitement; staggers
Locoweed (Astragalus)
MOA
Characteristics
Toxic principle: swainsonine
Inhibits alpha-mannosidase, rsulting in mannose-containing vacuoles in the CNS neurons, esp cerebellar neurons
Tremors, ataxia, proprioceptiv deficits
Organophosphate and carbamate insecticides
MOA
Characteristics
Acute nicotinic effects of cholinesterase inhibition allow acetylcholine excess at neurons
Mm fasciculations and tremors leading to paralysis at high dosages
Rayless goldenrod (haplopapus)
MOA
Characteristics
Unknown
Similar to white snakeroot
Rye grass (lolium perenne)
MOA
Characteristics
An endophytic fungus in teh grass produces the toxin lollitrem B, which is assoc with changes in GABA neurotransmitter
Tremors and ataxia (staggers), weakness in cattle, sheep and horses
Tremorgenic mycotoxins
MOA
Characteristics
Penitrem A, produced by several Penicillium spp, faiclitates impulse transmission at motor endplates by increasing the restin gpotential, endplate potential and length of depolarization phase; inhibitory neurontramssions (gaba, glycine) may be inhibited
Mm tremors, ataxia, incoordination, weakness; may progress to death
White snake root (eupatorium)
MOA
Characteristics
Unknown
Tremetone (formerly called tremetol) and it dihydro- and hydroxy analogs cause ataxia, weakness, continuous tremors, which may worsen when the animal is exercised or excited; cattle exhibit primarily the neurologic syndrome, but horses develop cardiac damage and arrythmias as well
