Memory improvement in ibotenic acid induced model rats by extracts of Scutellaria baicalensis

Ethnopharmacological relevanceScutellaria baicalensis Georgi (Labiatae) extracts have been used as traditional Korean medicine, to treat cerebral ischemia in addition to bacterial infection and inflammatory diseases.Aim of the studyThe improvement effect on learning and memory by the administration of Scutellaria baicalensis extracts was evaluated and the underlying mechanisms were investigated.Materials and methodsMemory behavior was tested by the passive avoidance test and Y-maze test. We also investigated the cells expressing neuronal markers related to memory processes by immunofluorescence staining analysis in memory deficient animal model (Ibo model) rats and in hippocampal progenitor cells.ResultsWe found neuronal cells immunoreactive to choline acetyltransferase (ChAT), a marker for cholinergic neurons were increased in the hippocampus, while cells producing GABA and glutamate were not after 30 mg/kg Scutellaria baicalensis administration. Futhermore, Scutellaria baicalensis extracts enhanced the survival of a hippocampal progenitor cell line, HiB5 and its differentiation to ChAT immunoreactive cells. The increased expression of memory related neurotransmitter, NMDA receptor and a reduction of activated microglia in the hippocampus were also observed in the Ibo model when administrated Scutellaria baicalensis extracts.ConclusionsThese results imply that Scutellaria baicalensis has significant neuroprotective effects in the Ibo model.