Conductance changes underlying a late synaptic hyperpolarization in hippocampal CA3 neurons.
Conductance changes underlying a late synaptic hyperpolarization in hippocampal CA3 neurons.
复制标题
海马 CA3 神经元晚期突触超极化的电导变化。
DOI：
10.1152/jn.1987.58.1.160
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发表时间：
1987
影响因子：
2.5
通讯作者：
Thalmann,RH
中科院分区：
文献类型：
--
作者：
Hablitz,JJ;Thalmann,RH
1.采用单电极电流钳和电压钳技术研究了大鼠海马脑片CA 3区锥体神经元顺向诱发的迟发性突触超极化或迟发性抑制性突触后电位（IPSP）的电导特性。2.晚期IPSPs可以发生在没有先前的兴奋性突触后电位在静息膜电位，并根据顺向刺激的强度进行分级。与晚期IPSP相关的膜超极化在顺向刺激苔藓纤维传入后140-200 ms内达到峰值。晚期IPSP恢复到基线，半衰减时间约为200 ms。从恒定振幅的超极化电流脉冲，膜电导的增加，在后期IPSP，其衰减的时间过程中，是相似的测量是否接近静息膜电位或当细胞超极化约35 mV。4.当向细胞外培养基中加入1 mM铯以减少内向整流时，可以在-60至-140 mV的膜电位范围内检查晚期IPSP。对于任何给定的神经元，晚期IPSP振幅-膜电位关系在相同的膜电位范围内是线性的，其中斜率输入电阻恒定。晚期IPSP在-95 mV附近对称逆转。5.细胞内注射乙二醇-双-（β-氨基乙基醚）-N，N '-四乙酸或细胞外应用毛喉素，已知可降低或阻断CA 3神经元中某些钙依赖性钾电导的程序，对晚期IPSP无显著影响。6.采用单电极电压钳技术分析晚期IPSP电流的时程和电压敏感性。这种电流[晚期抑制性突触后电流（IPSC）]早在顺向刺激后25 ms就开始，并在刺激后120-150 ms达到峰值。7.晚期IPSC以单一指数时间过程（τ = 185 ms）衰减。8.在生理浓度的细胞外钾（3.5 mM）中观察到晚期IPSC在约-99 mV处的明显逆转。（400字处截断摘要）
1. Single-electrode current- and voltage-clamp techniques were employed to study properties of the conductance underlying an orthodromically evoked late synaptic hyperpolarization or late inhibitory postsynaptic potential (IPSP) in CA3 pyramidal neurons in the rat hippocampal slice preparation. 2. Late IPSPs could occur without preceding excitatory postsynaptic potentials at the resting membrane potential and were graded according to the strength of the orthodromic stimulus. The membrane hyperpolarization associated with the late IPSP peaked within 140-200 ms after orthodromic stimulation of mossy fiber afferents. The late IPSP returned to base line with a half-decay time of approximately 200 ms. 3. As determined from constant-amplitude hyperpolarizing-current pulses, the membrane conductance increase during the late IPSP, and the time course of its decay, were similar whether measurements were made near the resting membrane potential or when the cell was hyperpolarized by approximately 35 mV. 4. When 1 mM cesium was added to the extracellular medium to reduce inward rectification, late IPSPs could be examined over a range of membrane potentials from -60 to -140 mV. For any given neuron, the late IPSP amplitude-membrane potential relationship was linear over the same range of membrane potentials for which the slope input resistance was constant. The late IPSP reversed symmetrically near -95 mV. 5. Intracellular injection of ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid or extracellular application of forskolin, procedures known to reduce or block certain calcium-dependent potassium conductances in CA3 neurons, had no significant effect on the late IPSP. 6. Single-electrode voltage-clamp techniques were used to analyze the time course and voltage sensitivity of the current underlying the late IPSP. This current [the late inhibitory postsynaptic current (IPSC)] began as early as 25 ms after orthodromic stimulation and reached a peak 120-150 ms following stimulation. 7. The late IPSC decayed with a single exponential time course (tau = 185 ms). 8. A clear reversal of the late IPSC at approximately -99 mV was observed in a physiological concentration of extracellular potassium (3.5 mM).(ABSTRACT TRUNCATED AT 400 WORDS)