Increased levels of the excitotoxin quinolinic acid in spinal cord following contusion injury

Products of inflammatory phagocytes are potential contributors to secondary pathology following spinal cord trauma. In the present study we quantified the levels of the neurotoxin and product of activated macrophages, quinolinic acid (QUIN), in the lower thoracic spinal cord of adult guinea pigs 5 days after brief compression injury. At the injured site (T13), elevations in tissue QUIN levels (> 10-fold) accompanied proportional increases in the activity of indoleamine-2,3 dioxygenase (> 2-fold) and the concentrations of l-kynurenine (> 2.5-fold). In contrast, no significant changes occured in two uninjured regions examined compared to controls, namely cervical spinal cord (C2) and the somatosensory cortex. Further studies of QUIN as a potential contributor to spinal cord injury are warranted.