Why is cocaine cut with levamisole?

According to recent studies, a large percentage of the world's cocaine supply is cut with levamisole. We have been following this story on DoseNation since June, but now it appears the trend is reaching epidemic proportions. Why is coke cut with levamisole, an animal de-wormer that weakens the immune system? MindHacks takes a closer look:

As an excellent article on Erowid notes, the fact that cocaine is cut with only small amounts of levamisole (only 6% of the deal in one study) suggests that it is not being used just as a handy powder to thin out the coke - more likely, it is being added for a specific effect.

Levamisole is, in some respects, similar to nicotine and the drug binds to specific nicotine-triggered receptors for the neurotransmitter acetylcholine and causes the nerve cell to respond. It turns out that this is most likely to increase activity in the body's 'fight-or-flight' system - the sympathetic nervous system...

As cocaine also stimulates the body, the two drugs could combine to cause additional arousal...

In the brain, levamisole likely also enhances the release of glutamate, a neurotransmitter that is known to encourage or excite the function of neurons.