If a chronic pain patient experiences increased pain despite consistent opioid dosage, which mechanism is most likely responsible for this phenomenon in dorsal horn nociceptor signaling?

💡 Explanation

Substance P is a key neurotransmitter involved in nociception, therefore an upregulation of substance P release enhances pain signaling in the dorsal horn, because the dorsal horn acts as a 'gate control' for modulating nociceptive signals. It is the body's pain highway; rather than decreased activity of descending inhibitory pathways.

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