Peripheral neurotoxicology Flashcards
measures of peripheral nerve function
organ functions such as HR breathing rate, and digestion
sensory perception - pain, sight, hearing
nerve and muscle function - electromyography and nerve conduction velocity
biochemical measures (not PNS specific) - neurofilament light chain, beta-endorphins, CRP, inflammatory cytokines, endocannabinoids
peripheral neuropathy and some neuroprotective + causative agents
loss of balance, coordination and reflexes. muscle weakness and poor nerve conduction and electromyography
can cause paresthesia, numbness and ulceration
glucose (diabetics), cisplatin, thalidomide, isoniazid, and statins are examples of causative agents
Alpha-lipoic acid, amifostine (for cisplatin), acetyl-carnitine (chemo) and pyridoxine (izoniazid)are neuroprotective
ciguatera fish toxicology mechanisms and therapy
contains ciguatoxins that are potent VGSC activators, causing nausea, vomiting, diarrhoea, convulsions, asphyxia, and death.
calcium channel blockers as a treatment (to prevent the AP as a result of the sodium activation)
Saxitoxin mechanisms
found in micro algae
STX inhibits sodium gated channels, causing respiratory paralysis and paralysis.
tetrodotoxin mechanisms
TTX found in fugu (puffer fish) and also produced by some bacteria
sodium channel blocker selective to nerves, with no antidote. Causes muscle weakness, ataxia, and respiratory or heart failure
Strychnine uses, mechanism and treatments
found in turkish rhubarb and used as an arrow poison and pesticide
inhibits the inhibitory glycine receptors, causing seizures and poor respiratory ventilation.
treated by anticonvulsants (phenobarbitone/diazepam, etc…)
snake and spider toxins examples and mechanisms
Brazilian jumping spider toxin causes priapism from calcium channel blockade
black widow contains a-latrotoxin, causing massive NT release from synaptic vesicles - exocytosis. Causes cramps, spasms, and even death rarely
banded krait has a-bungarotoxin which inhibits nAChRs - paralysis. some mild CNS nAChR antagonism too
Organophosphates uses, mechanisms and treatments
weapons: sarin, VX, novichok, malathion
insecticides: parathion, diazinon, chlorpyrifos
inhibits AChE, causing accumulation of ACh - toxicity. cholinergic syndrome - bradycardia, cramps, bronchoconstriction, blurred vision, vomiting, respiratory depression, convulsions, coma, etc…
treated by anticholinergics, e.g., atropine, pralidozime (an antagonist that leads to AChE regeneration)
can also treat with activated charcoal and airway stabilisation
Botulism mechanism
botulinum toxin produced by clostridium botulinum living in soil and animal intestines
can contaminate through food or infection of wounds, causing inhibition of muscle innervation, paralysis, blurred vision, difficulty swallowing, and respiratory paralysis
binds to presynatpic membranes of motor neurone nerves, preventing the release of ACh
also can be used in very small amounts for botox treatment
