Question

Describe how storage and release of acetylcholine are affected by the following: vesamicol, black widow spider venom, and botulinum toxin.

Answer 1

Vesicles are loaded w/ ACh by the transport protein in the vesicle membrane called VAChT - vesicular ACh transporter. This protein may be blocked by the drug called vesamicol. Treatment with vesamicol can decrease vesicular ACh but increases the level of ACh in the cytoplasm.

Release of ACh is affected by the various animal and bacterial toxins (toxin in venom of black widow) that leads to massive release of ACh at the synapses in PNS. Overactivity of cholinergic system can cause many symptoms such as muscle pain in abdomen or chest, tremors, nausea etc.

Toxins that are responsible to cause botulism poisoning can inhibit ACh release. This inhibition can be deadly because of muscle paralysis.