Abstract: Previous work demonstrated that there was learning-dependent long-term potentiation (LDLTP)of synaptic efficacy at the PP-CA3 synapses of rats during learning.In the present study it was further observed that LDLTP happened synchronously at MF-CA3 and Comm-CA3 synapses in learning,but the potentiation degree of MF-CA3 synapse was much larger than that of Comm-CA3 synapse(P<0.01). previous work showed again that the injection of picrotoxin, GABA receptor antagonist, facilitated the production of LDLTP at PP-CA3 synapse during training, In this study, it was found that the injection of picrotoxin into the ipsilateral CA3 area could facilitate the production of LDLTP at contralateral MF-CA3 synapse and correspondingly the behavioral response.These results demonstrated that LDLTP can be induced at the synapses of several inputs in hippocampal CA3 during learn ing and both lateral CA3 areas coordinate each other for the induction of LDLTP.

Key words: Long-term potentiation, Learning, Memory, Hippocampus, Mossy fiber, Commissural fiber, Picrotoxin