Effects of morphine on synaptic transmission of rat hippocampal neurons and its mechanisms
Abstract：AIM: To investigate the effects of morphine on synaptic transmission of neurons of central nervous system and to understand its mechanisms.METHODS: The hippocampus neurons were isolated from newborn Wistar rats for primary culture, and whole-cell patch-clamp technique was employed to observe the excitatory and spontaneous inhibitory postsynaptic currents (EPSC,sIPSC) and glutamate-evoked current before and after morphine treatment.RESULTS: sEPSC of the hippocampal neurons was increased by 207.8%( t =42. 1828, P ＜ 0.01) after morphine application, and the effect was blocked by opioid antagonist naloxone. The frequency of mEPSC and the amplitude of glutamate-evoked current of the hippocampal neurons did not undergo significant changes after morphine treatment( t =0. 962, 0. 791, respectively, P ＞ 0.05). Morphine markedly inhibited sIPSC of the hippocampal neurons, the effect of which was blocked by naloxone( P ＜ 0.01).CONCLUSION: The excitatory effect of morphine on hippocampal neurons is not due to the direct action of morphine on glutamate synapses transmission, but can be a result of the inhibition on the interneurons, or, through the "disinhibition" mechanism.
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Publication Date：2004-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：2( 774-775 )