My answer to What is the relationship between opiates/opioids, and dopamine?

Answer by Connie b. Dellobuono:

Opiates binding to opiate receptors in the nucleus accumbens: increased dopamine release

This is a close-up view of a synapse in the nucleus accumbens. Three types of neurons participate in opiate action: one that releases dopamine (on the left), a neighboring terminal (on the right) that contains a different neurotransmitter (probably GABA for those who would like to know), and the post-synaptic cell that contains dopamine receptors (in pink). Show that opiates bind to opiate receptors (yellow) on the neighboring terminal and this sends a signal to the dopamine terminal to release more dopamine. [In case someone asks how, one theory is that opiate receptor activation decreases GABA release, which normally inhibits dopamine release, so dopamine release is increased.]

Opiates binding to opiate receptors in the nucleus accumbens: increased dopamine release

What is the relationship between opiates/opioids, and dopamine?