✓ Concentrations of norepinephrine (NE), dopamine (DA), serotonin (5-HT), and histamine (HIST) were determined in spinal cords of five groups of cats. One group underwent laminectomy only; a second untreated group received a 400 gm-cm impact at the T-9 level. These were compared with three 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 hour after trauma. There was no change in NE concentration in any of the three 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.
The syndrome of autonomic dysreflexia often occurs in quadriplegic subjects and is characterized by paroxysmal hypertension, headache, vasoconstriction below and flushing of the skin above the level of transection, and bradycardia. These attacks may cause hypertnesive encephalopathy, cerebral vascular accidents, and death. In five patients during crises, the mean arterial pressure changed from 95 to 154 mm Hg, heart rate 72 to 45 beats/min, cardiac output 4.76 to 4.70 L/min, and peripheral resistance 1650 to 2660 dynes.sec.cm-5. In eight subjects the control plasma, red cell, and total blood volumes were 19.1, 10.5, and 29.6 ml/cm body height, respectively, and when hypertensive, the plasma protein concentration increased by 9.9% and the hematocrit by 9.5%. Plasma volume was only reduced by an estimated 10-15%. At that time, arterial dopamine-beta-hydroxylase (DbetaH) activity increased 65% and prostaglandin E2 concentration by 68%. Thus, the augmented DbetaH activity presented primarily an elevated sympathetic tone and not hemoconcentration of that protein. The rise in prostaglandin may contribute to the severe headaches during hypertensive episodes.
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