Activation of metabotropic glutamate receptor 1a aggravates traumatic brain injury.The constitutively expressed protein Homerlb/c participates in delivering and anchoring metabotropic glutamate receptors in neurons.Here,we aimed to verify whether down-regulation of Homerlb/c by RNA interference could protect cultured rat cortical neurons from traumatic injury.We showed that 36 hours after transfection of Homerlb/c small interfering RNA,metabotropic glutamate receptor 1a was present only in the neuronal cytoplasm,but not in the dendrites.Calcium fluorescence intensity was also decreased significantly.Moreover,lactate dehydrogenase concentration was significantly decreased in Homer1 b/c small interfering RNA-transfected cells compared with that in untransfected and control small interfering RNA-transfected cells 24 hours after traumatic neuronal injury.Our findings indicate that down-regulation of Homerlb/c could reduce metabotropic glutamate receptor 1a transfer from the cell body to the dendrite,relieve calcium overload,and protect neurons from traumatic injury.