Spinal cord energy metabolism in normal and postlaminectomy cats

The purpose of this study was to determine 1) normal concentrations of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), phosphocreatine (P-creatine), glucose, lactate, and pyruvate in upper (L-2) and lower (L-5) feline lumbar spinal cord, and 2) whether previously reported laminectomy-induced reduction in spinal cord blood flow (SCBF) resulted in disturbance of spinal cord energy metabolism. Concentrations of ATP, P-creatine, pyruvate, and glucose were significantly higher at L-5 than at L-2, probably as the result of larger amounts of gray matter at L-5 than L-2. Significant increases in ADP and AMP levels were the only metabolite changes noted 15 minutes following laminectomy. The authors speculate that the increase in ADP and AMP is due to a laminectomy-induced stimulation of ATP utilization. However, lack of change in other metabolites implies an efficient energy homeostasis. These results indicate that although laminectomy can reduce SCBF, the degree of this reduction is insufficient to adversely affect spinal cord energy metabolism. Thus, tissue from beneath or near the laminectomy site is viable and essentially normal.