Changes of mRNA of metabotropic glutamate receptor 4 after diffuse brain injury and diffuse brain injury with secondary brain insults. A: in the sham-operated group, few mGluR4 positive neurons were found. B: the number of mGluR4 positive neurons increased and peaked 6 hours after DBI. C: the number of mGluR4 positive neurons in the DBI with SBI group was even higher than that in the DBI alone group. The arrows point at the positive neurons.