To investigate the effect of Tiaoxin Recipe (TXR) on long-term potentiation in hippocampal slices of rats. Population spikes (PS) in CA1 area of rats hippocampal slices were evoked by extracellular microelectrode recording technique

and tetanic stimulation (100Hz

100 pulses) was used to induce long-term potentiation (LTP). The successful rate of evoking LTP was about 60% under normal condition

the PS amplitude increased after stimulation

whereas PS latent period decreased obviously. Pre-incuba-tion of hippocampal slices with TXR (7. 45 mg/ml) showed little effect on either the shape or amplitude of PS

indicating it didn’t influence the basal synaptic transmission. However

after tetanus

the LTP induction rate and PS amplitude were significantly enhanced compard with the control. TXR facilitates LTP induction rate and PS amplitude in rat hippocampal slices

which might be one of the mechanisms of TXR in improving learning and memory function of hippocampus.