Abstract
In the present study, we studied the neuroprotective effects of berberry extract (BE) against ischemic damage and the temporal and spatial alterations of N-methyl-D-aspartate receptor type 1 (NR1) and NR2A/2B immunoreactivities in the gerbil hippocampal CA1 region after transient ischemia to examine anti-ischemic effects and its role in transient forebrain ischemia. In the vehicle-treated group, the percentage of cresyl violet positive pyramidal cells in the CA1 region was about 11.4% compared to the sham-operated group 4 d after ischemic insult. BE showed neuroprotective effects against ischemic damage after ischemia-reperfusion. In the BE-treated groups, about 60—75% of CA1 pyramidal cells were stained with cresyl violet 4 d after ischemic insult. We observed the percentage of berberine (7.45+0.85 mg/g in BE) by HPLC, which is active ingredient of BE. NR1 immunoreactivity in the stratum pyramidale of the CA1 region in the vehicle-treated group was significantly increased at 30 min after transient forebrain ischemia, while at this time the NR1 immunoreactivity in the BE-treated groups was significantly low compared to the vehicle-treated group. The pattern of NR2A/B immunoreactivity in the stratum pyramidale of the BE-treated group and its protein levels were similar to that in the vehicle-treated group after ischemic insult. These results suggest that BE has potent neuroprotective effects against ischemic damage via the reduction of NR1 activity.
