Oleuropein Improves Long Term Potentiation at Perforant Path-dentate Gyrus Synapses in vivo

Abstract Objective To investigate the effect of oleuropein (OE) on long term potentiation (LTP) at hippocampal perforant path-dentate gyrus synapses in vivo. Methods An outer guide cannula, a monopolar recording electrode, and a bipolar stimulating electrode were implanted in the skull and extracellular recording technique was used to record the population spike in the dentate gyrus of anesthetized rats. Results Oleuropein significantly increased the basal synaptic transmission and the amplitude of population spike was increased from (117.6 ± 2.3)% to (134.9 ± 3.7)% after administration with OE. OE also accelerated LTP induction and maintenance, the population spike amplitude after high frequency stimulation was increased from (167.2 ± 12.8)% to (225.5 ± 15.5)% and the maintenance phase of LTP was from (182.1 ± 15.1)% to (210.5 ± 9.0)% respectively after administration with OE. Conclusion Present study showed that OE significantly improved different stages of LTP, which could be the molecular mechanism of its efficacy on attenuating AD-like pathology and delaying cognitive decline. OE can be a promising drug for AD and dementia.