Substance P has what role in tissue injury pain?

Prepare for the Tissue Injury, Healing, and Pain Test. Utilize flashcards and multiple-choice questions with hints and explanations. Ensure you're ready for the exam!

Substance P is a neuropeptide released from primary sensory neurons in response to tissue injury, and it drives both peripheral sensitization and enhanced pain signaling. It acts on NK1 receptors on nociceptors and nearby cells to lower their activation threshold, making them more responsive to ongoing or new noxious stimuli. In the tissue, Substance P also promotes neurogenic inflammation by causing vasodilation and increased vascular permeability, which leads to edema and further sensitizes the local environment to pain. In the spinal cord, it facilitates transmission of pain signals, contributing to central sensitization and heightened pain perception. This combination—making nociceptors more responsive and promoting pain signaling—fits the role of Substance P in tissue injury pain. It does not inhibit nociceptors, act only on motor signaling, or neutralize inflammatory mediators; instead, it enhances both inflammation and pain signaling.