The neuroprotective effect of propofol against brain ischemia mediated by the glutamatergic signaling pathway in rats

Several mechanisms are involved in the neuroprotection of propofol against ischemia, but influences of propofol on the binding properties of glutamate receptors and the uptake of glutamate in brain ischemia are not known. The present study was undertaken to investigate these issues in rat global brain ischemic model using methods of neuropathological evaluation, radioligand binding assay with and uptake test for L-³H-glutamate. It was shown that propofol used in anesthetic doses protected pyramidal neurons in the hippocampal CA1 subfield against delayed neuronal death normally induced by global brain ischemia. Simultaneously, the propofol decreased the value of maximal number of binding sites (Bmax), increased the value of equilibrium dissociation constant (Kd), and increased the glutamate uptake in the CA1 subfield. These findings indicate that it is, at least partly, via modulating the binding properties of glutamate receptors and the uptake of glutamate that propofol protects neurons against ischemic injury.