Hyperpolarization activated cyclic nucleotide-gated cation channels involved in central nervous system diseases:research advances / 国际药学研究杂志

Hyperpolarization activated cyclic nucleotide-gated cation (HCN) channels are involved in neuronal rhythm regulation, synaptic activity, membrane resistance and dendritic integration due to their voltage-gated physiological properties. Recent studies have shown that HCN channels play an important role in central nervous system diseases, such as temporal lobe epilepsy, neuropathic pain, learning and memory disorder, substance abuse addiction and other related diseases. In this paper, we summarize the research progress of HCN channels in central nervous system diseases in recent years.

Effects and mechanisms of morphine on synaptic transmission of hippocampal neurons of rat / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of morphine on synaptic transmission of neurons of central nervous system and reveal the mechanism underlying it.</p><p><b>METHODS</b>New born wistar rats were used for primary culture of hippocampus neurons. Using whole-cell patch-clamp technique, we observed the excitatory and spontaneous inhibitory postsynaptic current (EPSC, sIPSC) and glutamate-induced current before and after morphine treatment.</p><p><b>RESULTS</b>(1) sEPSC of hippocampal neurons was markedly increased after morphine application. The effect of morphine was blocked by opioid antagonist naloxone (n=18, P < 0.01). (2) The frequency of mEPSC and the amplitude of glutamate-induced current of hippocampal neurons had no significant changes after morphine treatment (P > 0.05). (3) Morphine inhibited sIPSC of hippocampal neurons markedly and naloxone could block this effect (n=13, P < 0.01).</p><p><b>CONCLUSION</b>The results suggest that the exciting effect of morphine on hippocampal neurons are not due to direct influence of morphine on glutamate synapses transmission, but may result from the inhibition on interneurons, that is "disinhibition" way.</p>

Effects of morphine on K+ currents in caudate nucleus of neonatal rat / 中国应用生理学杂志

<p><b>AIM</b>The effects of morphine on the potassium ionic currents of caudate nucleus neurons of neonatal rat were studied.</p><p><b>METHODS</b>Using of whole cell voltage clamp technique on caudate nucleus neurons, applied morphine chronically or acutely on it. In order to research the effects of morphine for voltage-gated of potassium ionic currents.</p><p><b>RESULTS</b>The amplitude of potassium ionic currents are increased by applied morphine acutely in caudate nucleus from (2.6 +/- 0.4) nA to (3.3 +/- 0.5) Na, naloxone can block the effect of morphine on K+ current and the currents are decreased to (2.4 +/- 0.4) nA. If applied morphine in caudate nucleus chronically, the amplitude of potassium ionic currents are increased from (2.6 +/- 0.4) nA to (3.1 +/- 0. 5) nA. After applied naloxone, the currents are decreased to (2.4 +/- 0.4) nA.</p><p><b>CONCLUSION</b>The effects of morphine increased potassium ionic currents by micro-opioid receptor mediated and induced the hyper polarization of neurons, leading to inhibition of neural activity.</p>