The following are ways that opioids can interupt pain signalling except:
A) opioid receptors are found on pain fiber terminals.
B) activation of opioid receptors in the spinal cord inhibit the release of substance P.
C) endogenous opioid levels increase in periaqueductal gray.
D) neurons release endogenous opioids in the medulla.

Question

Quizplus · Accepted Answer

The correct answer is C because the increase of endogenous opioid levels in the periaqueductal gray (PAG) is not a direct way opioids interrupt pain signaling. Instead, the PAG is involved in the descending modulation of pain, where it can activate inhibitory pathways that reduce pain perception. The other options directly relate to how opioids can interrupt pain signaling at various points in the pain pathway.

The Following Are Ways That Opioids Can Interupt Pain Signalling