Nongenomic effect of levothyroxine on the synchronous electrical activity of the spinal dorsal horn in the rat

Abstract

Levothyroxine (T₄) has a well-known effect on the central nervous system (CNS). This effect requires hours of latency by genetic pathway. We tested for short latency nongenomic effects of T₄ superfusion on the spinal dorsal horn (DH) evaluating lumbar somatosensory evoked potentials in rats. T₄ increased N and P wave amplitudes and N wave area under the curve, but reduced P wave duration and N–P interval, suggesting that T₄ exerts both excitatory and synchronizing effects on DH interneurons in less than 300 s, thus, providing evidence of nongenomic effects of T₄ on DH.

• Levothyroxine
• spinal dorsal horn
• spinal evoked potentials

Acknowledgements

Thanks to M. Pinto and A. Arveláez for their technical help, to Dr V. Vivas-O’Connor for the critical reading of the manuscript, and to Dirección de Investigación y Producción Intelectual, FCS-Universidad de Carabobo, for animal supply.