Steady-State Levels of Monoamines in the Rat Lumbar Spinal Cord: Spatial Mapping and the Effect of Acute Spinal Cord Injury

Brian R. Noga, Alberto Pinzon, Riza P. Mesigil, Ian D. Hentall
2004 Journal of Neurophysiology  
Noga, Brian R., Alberto Pinzon, Riza P. Mesigil, and Ian D. Hentall. Steady-state levels of monoamines in the rat lumbar spinal cord: spatial mapping and the effect of acute spinal cord injury. . Monoamines in the spinal cord are important in the regulation of locomotor rhythms, nociception, and motor reflexes. To gain further insight into the control of these functions, the steady-state extracellular distribution of monoamines was mapped in the anesthetized rat's lumbar spinal cord. The effect
more » ... of acute spinal cord lesions at sites selected for high resting levels was determined over ϳ1 h to estimate contributions to resting levels from tonic descending activity and to delineate chemical changes that may influence the degree of pathology and recovery after spinal injury. Measurements employed fast cyclic voltammetry with carbon fiber microelectrodes to give high spatial resolution. Monoamine oxidation currents, sampled at equal vertical spacings within each segment, were displayed as contours over the boundaries delineated by histologically reconstructed electrode tracks. Monoamine oxidation currents were found in well defined foci, often confined within a single lamina. Larger currents were typically found in the dorsal or ventral horns and in the lateral aspect of the intermediate zone. Cooling of the low-thoracic spinal cord led to a decrease in the oxidation current (to 71-85% of control) in dorsal and ventral horns. 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doi:10.1152/jn.01035.2003 pmid:15014108 fatcat:23lbrojd6netlpgl3gqa57ubr4