Toxic Plants - 1 Flashcards
Describe the mechanism of action of insoluble calcium oxalates
- contain needle shaped calcium oxalate crystals that penetrate the oral mucosa, tongue, and throat, causing irritation
- some species produce proteolytic enzymes which cause the release of histamine and kinins, increasing damage
Describe the mechanism of action of soluble oxalates
hypocalcemia and precipitation of insoluble calcium oxalates in soft tissues, and kidney damage
Describe the mechanism of action of isocupressic acids
- vasoconstriction and decrease uterine blood flow which stimulates release of fetal cortisol and results in abortion
Describe the mechanism of action of quinones
- primary photosensitization
- due to presence of a photodynamic substance in the blood of animal and exposure to sunlight in predisposed animals
- reactions in lightly pigmented or unpigmented areas of skin
Describe the mechanism of action of tannic acids
- tissue damage including GI lesions and kidney damage
- mainly GI and kidney damage in ruminants
- mainly GI in monogastrics
What are the clinical signs of tannic acid toxicosis in ruminants?
In monogastrics?
R: constipation, brown urine, anorexia, depression, rumen atony
M: GI signs
Describe the mechanism of action of triterpene acids
- liver damage and hepatogenic photosensitization
- Lantadene A and B cause damage of bile canaliculi membranes and cholestasis
- decreased elimination of phylloerythrin, which causes photosensitization
Which species are most susceptible and which are most resistant to triterpene acid toxicosis?
- ruminants susceptible
- horses resistant
What are the clinical signs of triterpene acid toxicosis?
- depression, anorexia, constipation, diarrhea
- icterus, photophobia, erythema, swelling, necrosis, and sloughing
Describe the mechanism of action of colchicine alkaloids
- anti-mitotic by binding to tubulin and inhibiting spindle formation during cell division
What are the clinical signs of colchicine toxicosis?
- stomatitis, nausea, vomiting, diarrhea, GI hemorrhage
- hypotension and cardiac arrhythmias
- respiratory signs
- renal and hepatic failure
- seizure and neuronal signs
- coagulopathies
- myelosuppression
Describe the mechanism of action of diterpene alkaloids
- competitive blockade of the nicotinic receptors at the muscle endplate
What are the clinical signs of diterpene alkaloid toxicosis?
- sudden death in cattle
- muscle weakness, staggering, stiffness, bloating, collapse
What is the antidote for diterpene alkaloid toxicosis?
physostigmine or neostigmine
Describe the mechanism of action of ergot alkaloids
- vasoconstriction and gangrene
- uterine contraction
- loss of hair and hooves
Describe the mechanism of action of indolizidine alkaloids
- inhibit lysosomal enzymes essential for formation of glycoproteins
- alteration of cellular function in brain and other organs
- nitropropanol causes peripheral neuronal degeneration and respiratory signs
- Se causes abnormal hoof and hair
What are the clinical signs of indolizidine alkaloid toxicosis?
- neuronal signs, animal acts crazy
- depression, incoordination, ataxia, circling, abnormal behavior
Describe the mechanism of action of lycorine
- emetic and purgative
- bulb is most toxic
What are the clinical signs of lycorine toxicosis?
- anorexia, salivation, vomiting, diarrhea, and hypotension
- large amounts can cause muscle tremors and seizures
Describe the mechanism of action of muscarinic alkaloids
- stimulation of muscarinic cholinergic receptors
- CNS stimulation
What is the antidote for muscarinic toxicosis?
atropine
Describe the mechanism of action of piperidine alkaloids
- nicotinic effects: ganglionic neuromuscular stimulation followed by blockade
- prevents fetal movement resulting in birth defects
What are the clinical signs of piperidine alkaloid toxicosis?
- ataxia, incoordination, and birth defects
Describe the mechanism of action of pyridine alkaloids
- nicotine and lobeline act on nicotinic receptors
- low doses cause depolarization
- high doses cause blockade
What are the clinical signs of pyridine alkaloid toxicosis?
- rapid onset
- excitation, salivation, lacrimation, vomiting, diarrhea and tachypnea
- muscle twitching, weakness, and dyspnea
- death due to resp failure
Describe the mechanism of action of pyrrolizidine alkaloids
- hepatotoxic
Describe the mechanism of action of solanine and solanidine alkaloids
- GI, CNS, respiratory, and cardiac
Describe the mechanism of action of taxine alkaloids
- cardiotoxic and GI
Describe the mechanism of action of xanthine alkaloids
- blocking adenosine receptors
- inhibiting phosphodiesterase
What are the clinical signs of xanthine alkaloid toxicosis?
- salivation, vomiting, colic, and diarrhea
- CNS stimulation and seizures
- muscle tremors
- tachycardia and hypotension
- urination
Describe the mechanism of action of alsike clover and red clover
- hepatotoxicity and sensitization in horses only
What are the clinical signs of alsike clover and red clover toxicosis?
lacrimation, photophobia, erythema, pruritis, edema, and sloughing of skin
Describe the mechanism of action of avocado
- cardiotoxicity in goats, horses, rabbits, and birds
- mastitis and agalactica in cattle, horses, goats, and rabbits
What is caused by black walnut toxicosis?
laminitis
What is caused by grape and raisin toxicosis?
- acute renal failure in dogs
- GI signs including vomiting
What is caused by lily toxicosis?
- nephrotoxicity in cats
- GI irritation in cats and dogs
Describe the mechanism of action of pigweed toxicosis
- acute nitrate poisoning causes methemoglobinemia
- chronic nitrate poisoning causes abortion
- soluble oxalates cause hypocalcemia and kidney damage
- renal tubular nephrosis
Describe the mechanism of action of red maple
hemolytic anemia, hemoglobinemia, and heinz body formation in horses
Describe the mechanism of action of senna
myotoxin causes skeletal muscle myopathy and cardiomyopathy
- seeds are most toxic
Describe the mechanism of action of yellow star thistle and russian knappweed
- equine nigropallidal encephalomalacia or chewing disease
- toxins interact with dopamine transporter resulting in death of dopminergic neurons in the brain
What are the clinical signs of yellow star thistle and russian knappweed toxicosis?
inability to eat or drink
drowsiness interrupted by excitation
dehydration
What are the clinical signs of macadamia nut toxicosis?
- weakness, depression, ataxia, tremors, hyperthermia, lameness, vomiting, colic, diarrhea, pale mucus membranes
