Hemorrhage or hypotension induces extensive Foslike immunoreactivity in the magnocellular neurosecretory cells in the supraoptic nucleus of the hypothalamus in rat, especially in the vasopressin neurons. The present s...Hemorrhage or hypotension induces extensive Foslike immunoreactivity in the magnocellular neurosecretory cells in the supraoptic nucleus of the hypothalamus in rat, especially in the vasopressin neurons. The present study was to explore the neurotransmitter mediating this effect. Microinfusion of the alpha-adrenergic blocker into the supraoptic nucleus reduced the hypotension-induced Fos, whereas beta-antagonist did not affect it significantly. Alpha1- and alpha2-antagonist, prazosin and yohimbine,both reduced the Fos-positive cell counts. However, the effective dosage of yohimbine was much larger. Alpha1-agonist, methoxamine, induced abundant Fos-like immnnoreactivity in the vasopressin cells in this nucleus,while beta-and alpha2-agonist did not elicit such effect.Administration of the noradrenergic re-uptake inhibitor,desipramine, to this nucleus to locally accumulate the spontaneously released noradrenaline from the nerve terminals also induced Fos expression, mostly in the vasopressin cells.展开更多
The main function of Nucleus raphe magnus (NRM) is mostly pain mediation. Our previous study has demonstrated that oxytocin (OXT) regulates antinociception through the central nervous system rather than the peripheral...The main function of Nucleus raphe magnus (NRM) is mostly pain mediation. Our previous study has demonstrated that oxytocin (OXT) regulates antinociception through the central nervous system rather than the peripheral organs, and pain stimulation increases OXT concentration in the NRM. The experiment was designed to investigate OXT in the rat NRM effect on pain modulation. The results showed that 1) pain stimulation increased OXT concentration in NRM perfusion liquid;2) Intra-NRM microinjection of OXT increased the pain threshold in a dose-dependent manner, whereas intra-NRM microinjection of OXT receptor antagonist, desGly-NH2, d(CH2)5[D-Tyr2, Thr-sup-4]OVT decreased the pain threshold;3) NRM pre-treatment with OXT receptor antagonist completely attenuated the pain threshold increase induced by intra-NRM administration of OXT. The data suggested that OXT in NRM was involved in antinociception via OXT receptors.展开更多
Objective: To observe the effects of morphine on the excitatory postsynaptic currents (EPSCs) and miniature EPSCs (mEPSCs) in rat supraoptic nucleus (SON) neurons and to explore its synaptic mechanism. Methods: Using ...Objective: To observe the effects of morphine on the excitatory postsynaptic currents (EPSCs) and miniature EPSCs (mEPSCs) in rat supraoptic nucleus (SON) neurons and to explore its synaptic mechanism. Methods: Using whole-cell voltage-clamp recording technique in the brain slices, the EPSCS and mEPSCs of rat SON neurons were recorded, respectively. Results: Morphine (20μmol/L) decreased the frequency of EPSCs and mEPSCs (by 65% for EPSCS and by 45% for mEPSCs), and reduced the amplitude of EPSCs by 44% in all SON neurons, but the amplitude distribution of mEPSCs was not affected. Conclusion: Morphine inhibits the excitatory transmissions via presynaptic mechanisms in SON neurons from rat brain slices.展开更多
文摘Hemorrhage or hypotension induces extensive Foslike immunoreactivity in the magnocellular neurosecretory cells in the supraoptic nucleus of the hypothalamus in rat, especially in the vasopressin neurons. The present study was to explore the neurotransmitter mediating this effect. Microinfusion of the alpha-adrenergic blocker into the supraoptic nucleus reduced the hypotension-induced Fos, whereas beta-antagonist did not affect it significantly. Alpha1- and alpha2-antagonist, prazosin and yohimbine,both reduced the Fos-positive cell counts. However, the effective dosage of yohimbine was much larger. Alpha1-agonist, methoxamine, induced abundant Fos-like immnnoreactivity in the vasopressin cells in this nucleus,while beta-and alpha2-agonist did not elicit such effect.Administration of the noradrenergic re-uptake inhibitor,desipramine, to this nucleus to locally accumulate the spontaneously released noradrenaline from the nerve terminals also induced Fos expression, mostly in the vasopressin cells.
文摘The main function of Nucleus raphe magnus (NRM) is mostly pain mediation. Our previous study has demonstrated that oxytocin (OXT) regulates antinociception through the central nervous system rather than the peripheral organs, and pain stimulation increases OXT concentration in the NRM. The experiment was designed to investigate OXT in the rat NRM effect on pain modulation. The results showed that 1) pain stimulation increased OXT concentration in NRM perfusion liquid;2) Intra-NRM microinjection of OXT increased the pain threshold in a dose-dependent manner, whereas intra-NRM microinjection of OXT receptor antagonist, desGly-NH2, d(CH2)5[D-Tyr2, Thr-sup-4]OVT decreased the pain threshold;3) NRM pre-treatment with OXT receptor antagonist completely attenuated the pain threshold increase induced by intra-NRM administration of OXT. The data suggested that OXT in NRM was involved in antinociception via OXT receptors.
文摘Objective: To observe the effects of morphine on the excitatory postsynaptic currents (EPSCs) and miniature EPSCs (mEPSCs) in rat supraoptic nucleus (SON) neurons and to explore its synaptic mechanism. Methods: Using whole-cell voltage-clamp recording technique in the brain slices, the EPSCS and mEPSCs of rat SON neurons were recorded, respectively. Results: Morphine (20μmol/L) decreased the frequency of EPSCs and mEPSCs (by 65% for EPSCS and by 45% for mEPSCs), and reduced the amplitude of EPSCs by 44% in all SON neurons, but the amplitude distribution of mEPSCs was not affected. Conclusion: Morphine inhibits the excitatory transmissions via presynaptic mechanisms in SON neurons from rat brain slices.
