The Pleasant Feeling Called a "High" Produced by Using Narcotics

Multiple Choice

The pleasant feeling called a "high" produced by using narcotics is due to:

A) an increase in the release of the neurotransmitter serotonin.
B) the opponent process caused by IV injection.
C) the drug attaching to sites normally receptive to endorphins.
D) the drug flooding neurotransmitter synapses with dopamine.