Abstract: AIM: To observe the effects of huperzine A(Hup-A) on excitatory synaptic transmission in CA1 pyramidal neurons of adult rat hippocampal slices and to gain an insight into the cellular electrophysiological mechanisms underlying the potentiation of learning and memory by Hup-A. METHODS: The intracellular recordings from CA1 pyramidal neurons in hippocampal slices related to learning and memory were made to analyze mechanisms of Hup-A actions on cell electrophysiological properties and excitatory postsynaptic potential (EPSP) evoked by stimulating Schaffer collaterals. RESULTS: (1) During bath of Hup-A (1 μmol/L), the changes of cell electrophysiological properties were not significant (P>0.05). (2) Superfusion of Hup-A (0.3-3.0 μmol/L, 15 min) increased amplitude, duration and area under curve of EPSPs, which was concentration-dependent, recoverable, but sensitive to atropine pretreatment (10 μmol/L, n=4). (3) Hup-A did not result in remarkable changes of depolarizing response induced by exogenous glutamate (n=5). CONCLUSION: By the facilitation of the synaptic transmissions, Hup-A may potentiate the activities of hippocampal CA1 pyramidal neurons, and its actions on EPSP is related to the excitation of muscarinic type of acetylcholinergic receptors.

Key words: Huperzine A, Hippocampus, Pyramidal neurons, Synaptic transmission, Learning and memory, Rat