Match each pair, and then click the Check button.

The first neurotransmitter to be discovered, there are low levels of it in people with Alzheimer's disease.
Associated with the action of the sympathetic nervous system, it's effects are enhanced by amphetamines ("speed").
An inhibitory neurotransmitter, Parkinson's patients have too little of it, schizophrenics too much.
Another inhibitory neurotransmitter, it's effects are enhanced by antianxiety drugs such as Valium.
the most common neurotransmitter, it is actually toxic to neurons.
Too little of this neurotransmitter has been shown to lead to depression, obsessions, and even suicide.
Our built-in pain-killer, it is structurally similar to opium and heroin.