Decreased Calbindin-immunoreactive Renshaw Cells (RCs) in the Lumbar Spinal Cord of the Ataxic Pogo Mice

Kim, Jin Seong; Kim, Jae Min; Son, Jin A; Han, Seung Yun; Kim, Chul Tae; Lee, Nam Seob; Jeong, Young Gil

Abstract

Calbindin D-28K (CALB) is one of the calcium-binding proteins which is assumed to be buffering, transport of Ca2+, and regulation of various enzyme systems. In the spinal cord, a subpopulation of calbindin-immunoreactive neurons located in the ventral portion of lamina VII, medial to the motoneuron column, has recently been proposed to be Renshaw cells (RCs), that mediate recurrent inhibition of spinal alpha-motoneurons, based on the anatomical location. In this study, we have performed to investigate the correlation between RCs containing high levels of CALB and motoneurons in the ventral horn of lumbar spinal cord of the ataxic pogo mice, that characterized by a failures of interlimb coordination, and prolonged excessive tone of hindlimb extensor muscles. We have shown that CALB immunoreactive RCs was significantly decreased in the ventral horn of lumbar spinal cord of the ataxic pogo mice (p.0.05), when compared with the control mice. Whereas, CALB immunoreactivity expression levels were no difference in the dorsal horn. Furthermore, CALB protein was significantly decreased in the lumbar spinal cord of the ataxic pogo mice (p.0.01). However, there were no difference in the cervical and thoracic spinal cord of the between control and pogo mice. These results suggest that motoneurons of ventral horn of the lumbar spinal cord might be more excited state, results in the decreased CALB immunoreactive RCs have not mediated a motoneuron excitability, in the atxic mice, pogo.