Unconventional muscle pain signaling

摘要

Substance P (SP) is a pain neurotrans-mitter that helps excite and transmit pain signals from neural cells in many organs. Though high levels of SP in muscle tissues and spinal fluid are frequently associated with chronic muscle pain, the role of SP in muscle pain transmission and perception remains unclear. Chia-Ching John Lin et al. (pp. 363-364) used mice that lacked SP signaling to test how SP contributes to muscle pain sensitivity. The researchers found that in contrast to the neurotransmitter's usual excitatory role, mice without SP signaling showed increased pain sensitivity after intramuscular acid injections compared with mice that had normal SP signaling.