Stratum lacunosum-moleculare interneurons of hippocampal CA1 region. I. Intracellular response characteristics, synaptic responses, and morphology
Stratum lacunosum-moleculare interneurons of hippocampal CA1 region. I. Intracellular response characteristics, synaptic responses, and morphology
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DOI：
10.1523/jneurosci.08-04-01400.1988
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发表时间：
1988-04
期刊：
影响因子：
8.8
通讯作者：
J. Lacaille;P. Schwartzkroin
中科院分区：
文献类型：
--
作者：
J. Lacaille;P. Schwartzkroin
从豚鼠海马脑片CA_1区腔隙分子层（L-M）的非锥体细胞（中间神经元）获得稳定的细胞内记录。这些中间神经元的细胞内反应特征明显不同于锥体细胞和其他中间神经元（篮状细胞和方向-肺泡中间神经元）的反应。L-M中间神经元具有高静息膜电位（-58 mV）、高输入电阻（64 M Ω）和大振幅（60 mV）、相对长持续时间（2 msec）的动作电位。一个大的后超极化（11 mV，34毫秒）后，一个单一的动作电位。大多数L-M中间神经元没有显示任何自发放电。荧光黄（LY）填充的L-M中间神经元显示非锥体形态。细胞通常呈梭形或多极，棘状，串珠状树突状突起在腔隙分子层、放射层和（有时）定向层中分支。静脉曲张的轴突起源于初级树突，沿着腔隙分子层投射，在放射层大量分支，并走向和进入神经层，偶尔进入起源。胞体位于CA_1的L-M区的细胞突起并不局限于CA_1区。部分L-M中间神经元的树突和轴突突起在陷窝-分子层上升，穿过海马裂，在齿状回分子层内走行。刺激海马主要传入纤维在L-M中间神经元诱发兴奋性和抑制性突触后电位（EPSP和IPSP）。EPSPs最有效地引起的纤维通路的刺激在横向切片，而IPSPs主要诱发时，主要途径刺激在纵向切片。我们已经确定了一个人口的interneurons细胞内的反应特性和形态明显不同于以前描述的锥体和nonpyramidal神经元的CA 1区。这些中间神经元在海马电路的可能作用进行了讨论。
Stable intracellular recordings were obtained from nonpyramidal cells (interneurons) in stratum lacunosum-moleculare (L-M) of the CA1 region of guinea pig hippocampal slices. The intracellular response characteristics of these interneurons were distinctly different from responses of pyramidal cells and of other interneurons (basket cells and oriens-alveus interneurons). L-M interneurons had a high resting membrane potential (-58 mV), a high input resistance (64 M omega), and a large amplitude (60 mV), relatively long duration (2 msec) action potential. A large afterhyperpolarization (11 mV, 34 msec) followed a single action potential. Most L-M interneurons did not display any spontaneous firing. Lucifer yellow (LY)-filled L-M interneurons showed nonpyramidal morphology. Cells were generally fusiform or multipolar, with aspinous, beaded dendritic processes ramifying in stratum lacunosum-moleculare, radiatum, and (sometimes) oriens. The varicose axon originated from a primary dendrite, projected along stratum lacunosum-moleculare, branched profusely in stratum radiatum, and coursed toward and into stratum pyramidale and occasionally into oriens. Processes of cells with somata in the L-M region of CA1 were not restricted to the CA1 region. The dendritic and axonal processes of some L-M interneurons were seen ascending in stratum lacunosum- moleculare, crossing the hippocampal fissure, and coursing in stratum moleculare of the dentate gyrus. Excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) were evoked in L-M interneurons from stimulation of major hippocampal afferents. EPSPs were most effectively elicited by stimulation of fiber pathways in transverse slices, whereas IPSPs were predominantly evoked when major pathways were stimulated in longitudinal slices. We have identified a population of interneurons with intracellular response characteristics and morphology distinctly different from previously described pyramidal and nonpyramidal neurons of CA1 region. The possible role of these interneurons in hippocampal circuitry is discussed.