THE INHIBITIVE EFFECT OF NITRIC OXIDE ON HIPPOCAMPAL NEURONS EXCITATION
一氧化氮抑制海马神经元兴奋的机制研究

The inhibitive effect of nitric oxide(NO) on cultured rat hippocampal CA1 neurons excitation stimulated by penicillin G(PG) was investigated. A slow and late type of intracellular NO production induced by PG(1000 IU/ml) was disclosed when monitored with laser scanning confocal microscopy (LSCM). Pretreatment of L-NNA(0-10μmol/L), an NO synthase inhibitor, could dose-dependently inhibit the NO production and increase the intercellular level glutamate(10min after PG stimulation) as well. L-NNA(0-10μmol/L) also tended to increase the immunoreactive methionine enkephalin(ir-M-ENK) level while the immunoreactive dynorphin B(ir-DYN-B) level was remained unchanged. Finally, β-FNA (100μmol/L, an M-ENK receptor inhibitor) but not nor-BIN(100μmol/L, a DYN receptor inhibitor) could inhibit the increase of intercellular level glutamate caused by L-NNA. Together, the following conclusion was made: NO induced by PG (1000 IU/ml) stimulation inhibit further neuron excitation by inhibit the level of M-ENK.