不同剂量甘丙肽拮抗剂在三叉神经主核对甘丙肽外向电流的双向作用

目的 在三叉神经主核(PrV) 上检测不同剂量甘丙肽拮抗剂M35 和M40 对甘丙肽外向电流的作用。方法 全细胞膜片钳记录技术。结果 0.01、0.03及0.1 μmol·L^-1 的M35, 使甘丙肽引发的外向电流分别抑制53.1%、40.4% 及27.2%; 但1、3 μmol·L^-1 M35 使甘丙肽外向电流分别增大16.2%及38.4%。而给予0.01 及0.03 μmol·L^-1M40 时, 甘丙肽外向电流增大93.7%及68.4%;0.3、1 及3 μmol·L^-1 M40 使甘丙肽外向电流分别抑制49.2%、69.9%及87.2%。结论 低浓度M35为甘丙肽拮抗剂, 高浓度M35 有甘丙肽激动剂作用;低浓度M40 为甘丙肽激动剂, 高浓度M40 为甘丙肽拮抗剂, PrV 同一神经元上可能存在不同甘丙肽亚型受体。

Biphase actions of galanin antagonists at different doses on galanin-evoked outward-current of trigeminal nucleus neurons in rats

Aim To observe the effects of galanin (Gal) antagonist M35 or M40 at different concentrations on the Gal-evoked outward-current in principal trigeminal nucleus (PrV) neurons.Methods The technique of whole-cell patch-clamp was used to record the change of membrane current.Results At doses of M35 0.01, 0.03 and 0.1 μmol·L^-1, the Gal-evoked outward- current decreased by 53.1%, 40.4% and 27.2%, respectively.While M35 1 and 3 μmol·L^-1, the current increased by 16.2% and 38.4%.At doses of M40 0.01 and 0.03 μmol·L^-1, the current increased by 93.7% and 68.4%, while for M40 0.3, 1 and 3μmol·L^-1, the current decreased by 49.2%, 69.9% and 87.2%, respectively.Conclusion M35 at low concentrations antagonizes the effect of Gal and at high concent rations acts as a Gal receptor agonist. Whereas M40 in high doses antagonizes the effect of Gal and in low doses exerts an autagonistic action. There may be different Gal subtype receptors in the same PrV neuron.