First 117 words of the document:
They decrease the activity of the brain and nervous system.
But, how do they actually work?
What answer should I put when the question paper asks?
Nerve cells send information from one cell to another by sending chemical
messages. These messages are called neurotransmitters. An electrical signal
travels down one nerve cell, causing it to release the neurotransmitter into a
small gap between cells called the synapse. The neurotransmitter travels
across the gap, binds to a protein on the receiving cell membrane called a
receptor, and causes a change (electrical, chemical or mechanical) in the
But, that wasn't the answer.