Wu Jianqun, Harney Sarah, Rowan Michael J, Anwyl Roger
Department of Physiology, Trinity College, Dublin 2, Ireland.
Neurosci Lett. 2008 May 9;436(2):235-8. doi: 10.1016/j.neulet.2008.03.027. Epub 2008 Mar 15.
The involvement of group I metabotropic glutamate receptors (mGluRs) and ryanodine receptors was investigated in the induction of LTP induced either by application of one standard high frequency stimulation (HFS) or by strong multiple HFS in the medial perforant path to granule cell synapse of the rat dentate gyrus. Whilst a standard brief HFS induced LTP close to 50%, strong stimulation consisting of multiple HFS induced a much larger LTP. mGluR5 was found to be partially involved in the induction of the enhanced LTP induced by the strong HFS but not in the standard LTP induced by the brief HFS. Thus the mGluR5 antagonists LY341495 and MPEP partially inhibited the induction of LTP induced by strong HFS but did not inhibit LTP induced by a standard HFS. Ryanodine was found to partially inhibit LTP induced by the strong HFS but not to inhibit the standard LTP induced by the brief HFS, demonstrating the involvement of Ca-induced Ca release from ryanodine-sensitive Ca stores in the former. These studies demonstrate that the large amplitude LTP induced by strong stimulation involves additional mechanisms to the LTP induced by brief HFS, in particular involving activation of mGluR5 and RyR-sensitive Ca stores.
研究了I型代谢型谷氨酸受体（mGluRs）和兰尼碱受体在大鼠齿状回颗粒细胞突触的内侧穿通通路中，通过施加一次标准高频刺激（HFS）或强烈多次HFS诱导长时程增强（LTP）过程中的作用。虽然标准的短暂HFS诱导的LTP接近50%，但由多次HFS组成的强烈刺激诱导的LTP要大得多。发现mGluR5部分参与了由强烈HFS诱导的增强型LTP的诱导，但不参与由短暂HFS诱导的标准LTP的诱导。因此，mGluR5拮抗剂LY341495和MPEP部分抑制了由强烈HFS诱导的LTP的诱导，但不抑制由标准HFS诱导的LTP。发现兰尼碱部分抑制由强烈HFS诱导的LTP，但不抑制由短暂HFS诱导的标准LTP，这表明在前者中存在从兰尼碱敏感的钙库中钙诱导钙释放的参与。这些研究表明，由强烈刺激诱导的大幅度LTP涉及到与短暂HFS诱导的LTP不同的额外机制，特别是涉及mGluR5和兰尼碱受体敏感的钙库的激活。
