03 July 2006

Bella the MG dog

When we covered Acetylcholine (Ach) in neurochem one of the disorders we discussed was myasthenia gravis (MG). MG is an autoimmune disorder in which your body produces antibodies that block the Ach receptors of the neuromuscular junction. What this means is that when a nerve cell releases Ach to initiate muscle contraction, the muscle cannot receive the signal. The most prominant symptom of the disease is catalepsy (the inability to initiate voluntary movement).

The video (click here) shows Bella, a small dog, who has MG. Initially she cannot stand up and when the vet administers a blink test, she shows no reaction. The vet gives Bella some Edrophonium chloride, a drug that temporarily increases Ach tone. Subsequently, Bella can be seen running and reacting to the blink test until the medication wears off (it's called a Tensilon test). Bella is now on Pyridostigmine, a longer acting drug that also increases Ach tone, and has 75% of a normal dog's ability.

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