Mild concussive head injury results in increased brain substance P immunoreactivity

Abstract

The neuroinflammatory neuropeptide substance P (SP) has been implicated in oedema development following traumatic brain injury. Whether the neuropeptide plays a role in concussive head injury is unknown. Accordingly, we have used a newly developed model of mild head injury in rats to characterise the release of SP following concussive brain injury. Following brain trauma, there was no evidence of motor or cognitive deficits over the ensuing 3 weeks. Despite this, increased SP immunoreactivity was present in perivascular axons, some pyramidal neurones and astrocytes when compared to sham animals. Our findings suggest that concussive brain injury predisposes an individual to diffuse brain swelling, which may have implications in the management of sports related concussion.