Independent Hertie Research Group, Max-Planck Institute for Brain Research, D-60528 Frankfurt am Main, Germany.
Biochem Biophys Res Commun. 2010 Mar 19;393(4):587-91. doi: 10.1016/j.bbrc.2010.02.019. Epub 2010 Feb 10.
Presynaptic glycine receptors (GlyRs) have been implicated in the regulation of glutamatergic synaptic transmission. Here, we characterized presynaptic GlyR-mediated currents by patch-clamp recording from mossy fiber boutons (MFBs) in rat hippocampal slices. In MFBs, focal puff-application of glycine-evoked chloride currents that were blocked by the GlyR antagonist strychnine. Their amplitudes declined substantially during postnatal development, from a mean conductance per MFB of approximately 600 pS in young to approximately 130 pS in adult animals. Single-channel analysis revealed multiple conductance states between approximately 20 and approximately 120 pS, consistent with expression of both homo- and hetero-oligomeric GlyRs. Accordingly, estimated GlyRs densities varied between 8-17 per young, and 1-3 per adult, MFB. Our results demonstrate that functional presynaptic GlyRs are present on hippocampal mossy fiber terminals and suggest a role of these receptors in the regulation of glutamate release during the development of the mossy fiber--CA3 synapse.
突触前甘氨酸受体 (GlyRs) 被认为参与调节谷氨酸能突触传递。在这里，我们通过在大鼠海马切片中的苔藓纤维末梢 (MFBs) 进行膜片钳记录来描述突触前 GlyR 介导的电流。在 MFBs 中，焦点喷雾应用甘氨酸会引发氯离子电流，该电流被 GlyR 拮抗剂士的宁阻断。它们的幅度在出生后发育过程中显著下降，从年轻动物中每个 MFB 的平均电导约 600 pS 下降到成年动物中的约 130 pS。单通道分析显示，多个电导状态在约 20 至约 120 pS 之间，与同型和异型 GlyRs 的表达一致。因此，估计的 GlyRs 密度在年轻动物的每个 MFB 中为 8-17 个，在成年动物中为 1-3 个。我们的结果表明，功能性突触前 GlyRs 存在于海马苔藓纤维末梢上，并表明这些受体在苔藓纤维-CA3 突触发育过程中对谷氨酸释放的调节中发挥作用。
