The effect of oral administration of birch sap on memory may be due to an increased expression of synaptic proteins and a higher number of synaptic vesicles in the hippocampal nerve terminals, thereby enhancing glutamate release in the hippocampus of these rats. Additionally, memory preservation in the birch sap-treated rats may be associated with its modulatory effects on cerebral blood flow.

Keywords：birch sap; memory function; glutamate release; synaptic proteins; synaptosome; hippocampus