Biogenic amine concentrations in traumatized spinal cords of cats: effect of drug therapy

Concentrations of norepinephrine (NE), dopamine (DA), serotonin (5 HT), and histamine (HIST) were determined in spinal cords of 5 groups of cats. One group underwent laminectomy only; a 2nd untreated group received a 400 gm cm impact at the T 9 level. These were compared with 3 groups treated with epsilon aminocaproic acid (EACA), methyl prednisolone sodium succinate (MP), and a combination of EACA and MP after similar trauma. The biogenic amines were measured in three 1 cm segments of the cord, rostral, middle, and caudal, 1 hr after trauma. There was no change in NE concentration in any of the 3 segments after impact compared with laminectomized controls, nor was the NE concentration in the impacted (middle) area higher than that in the rostral or caudal sites. Although the NE content of the cord in treated animals decreased compared to that of laminectomized controls, the decrease was not significant. The concentration of DA, however, significantly increased after impact and significantly decreased after treatment with EACA and EACA plus MP. There was no significant change in 5 HT levels, but the level of HIST increased significantly after impact and was lowered by treatment with EACA and EACA with MP. The implications of these changes in biogenic amines in spinal cord trauma are discussed.