Electrophysiological and pharmacological characterization of the direct perforant path input to hippocampal area CA3
Electrophysiological and pharmacological characterization of the direct perforant path input to hippocampal area CA3
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DOI：
10.1152/jn.1998.79.4.2111
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发表时间：
1998-04-01
影响因子：
2.5
通讯作者：
Barrionuevo, G
中科院分区：
文献类型：
--
作者：
Berzhanskaya, J;Urban, NN;Barrionuevo, G
在大鼠海马脑片CA 3区锥体细胞上记录了刺激海马下针诱发的单突触穿通径反应。这些单突触反应是通过使用低强度的刺激和通过放置一个切口通过苔藓纤维分离。穿孔路径诱发的反应包括兴奋和抑制成分。兴奋性突触后电流（EPSC）由α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPAR）和N-甲基-D-天冬氨酸受体（NMDAR）介导。抑制性突触后电流由γ-氨基丁酸A（GABA（A）-）和γ-氨基丁酸B（GABA（B））受体介导的成分组成。在膜电位大于-60 mV和生理性[Ca ~（2+）]/[Mg ~（2+）]比值时，>30%的穿通通路诱发的EPSC由NMDAR介导。该值作为膜电压和外部[Mg 2 +]的函数而变化。低强度刺激穿支通路后，可观察到两种类型的反应，第一种反应表现为成对脉冲易化，可被2-氨基-4-膦酰基丁酸（AP 4）减弱。第二种反应表现为双脉抑制，巴氯芬可降低其反应。这两类反应的电生理和药理学特征与齿状回外侧和内侧穿支诱发的EPSP的性质相似。
Monosynaptic perforant path responses evoked by subicular stimulation were recorded from CA3 pyramidal cells of rat hippocampal slices. These monosynaptic responses were isolated by using low intensities of stimulation and by placing a cut through the mossy fibers. Perforant path-evoked responses consisted of both excitatory and inhibitory components. Excitatory postsynaptic currents (EPSCs) were mediated by both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) and N-methyl-D-aspartate receptors (NMDAR). Inhibitory postsynaptic currents consisted of gamma-aminobutyric acidA (GABA(A)-) and -B (GABA(B))-receptor-mediated components. At membrane potentials more positive than -60 mV and at physiological [Ca2+]/[Mg2+] ratios, >30% of perforant path evoked EPSC was mediated by NMDARs. This value varied as a function of the membrane voltage and external [Mg2+]. Two types of responses were observed after low-intensity stimulation of the perforant path. The first type of response showed paired-pulse facilitation and was reduced by 2-amino-4-phosphonobutyric acid (AP4). The second type of response showed paired-pulse depression and was reduced by baclofen. Electrophysiological and pharmacological characteristics of these two types of responses are similar to the properties of lateral and medial perforant path-evoked EPSPs in the dentate gyrus.