Glutamate enhances DNA fragmentation in cultured spinal motor neurons of rat.

The role of glutamate in the mechanism of spinal motor neuron death is not fully understood. With addition of glutamate to primary culture of 11-day-old rat spinal cord, terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) positive nuclei were found in spinal large motor neurons from 24 h, and the number of TUNEL positive large motor neurons greatly increased at 48 h. In contrast, only a small number of large motor neurons became TUNEL positive at 48 h with addition of vehicle to the primary spinal cord culture. The present results show that excessive amount of glutamate enhances DNA fragmentation in developing large motor neuron of cultured spinal cord by involving in apoptotic process of the neurons.