Effects of A Voltage Sensitive Calcium Channel Blocker and A Sodium-Calcium Exchanger Inhibitor on Apoptosis of Motor Neurons in Adult Spinal Cord Slices

OBJECTIVE The apoptosis of motor neurons is a critical phenomenon in spinal cord injuries. Adult spinal cord slices were used to investigate whether voltage sensitive calcium channels and Na(+)/Ca(2+) exchangers play a role in the apoptosis of motor neurons. MATERIALS AND METHODS In this experimental research, the thoracic region of the adult mouse spinal cord was sliced using a tissue chopper and the slices were incubated in a culture medium in the presence or absence of N/L type voltage sensitive calcium channels blocker (loperamide, 100 µM) or Na(+)/Ca(2+) exchangers inhibitor(bepridil, 20 µM) for 6 hours. 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium (MTT) staining was used to assess slice viability while morphological features of apoptosis in motor neurons were studied using fluorescent staining. RESULTS After 6 hours in culture, loperamideand bepridil not only increased slice viability, but also prevented motor neuron apoptosis and significantly increased the percentage of viable motor neurons in the ventral horns of the spinal cord. CONCLUSION The results of this study suggest that voltage sensitive calcium channels and Na(+)/Ca(2+) exchanger might be involved in the apoptosis of motor neurons in adult spinal cord slices.