Which molecules are most closely associated with pain sensation at tissue injury sites?

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Multiple Choice

Which molecules are most closely associated with pain sensation at tissue injury sites?

Pain at a tissue injury site mainly comes from local inflammatory mediators that directly sensitize nociceptors. The best-known trio that directly and acutely promotes this sensory change are bradykinin, prostaglandin E2, and substance P. Bradykinin binds to receptors on nociceptors, causing immediate activation and a burning pain signal. Prostaglandin E2, produced in response to injury, lowers the threshold of nociceptors so they respond more readily to painful and even non-painful stimuli, amplifying the pain signal. Substance P, released from the endings of sensory neurons, drives neurogenic inflammation by causing vasodilation and plasma leakage, which further promotes nociceptor sensitization and pain transmission. Cytokines like IL-6, TNF, and IFN-γ can contribute to pain by sensitizing nociceptors more broadly, but the immediate, site-specific pain sensation in tissue injury is most closely linked to bradykinin, PGE2, and substance P. Metabolic hormones such as adrenaline, cortisol, dopamine, and the listed metabolic peptides are not the primary local mediators driving nociceptor sensitization at the injury site.

Pain at a tissue injury site mainly comes from local inflammatory mediators that directly sensitize nociceptors. The best-known trio that directly and acutely promotes this sensory change are bradykinin, prostaglandin E2, and substance P. Bradykinin binds to receptors on nociceptors, causing immediate activation and a burning pain signal. Prostaglandin E2, produced in response to injury, lowers the threshold of nociceptors so they respond more readily to painful and even non-painful stimuli, amplifying the pain signal. Substance P, released from the endings of sensory neurons, drives neurogenic inflammation by causing vasodilation and plasma leakage, which further promotes nociceptor sensitization and pain transmission.

Cytokines like IL-6, TNF, and IFN-γ can contribute to pain by sensitizing nociceptors more broadly, but the immediate, site-specific pain sensation in tissue injury is most closely linked to bradykinin, PGE2, and substance P. Metabolic hormones such as adrenaline, cortisol, dopamine, and the listed metabolic peptides are not the primary local mediators driving nociceptor sensitization at the injury site.

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