Nicotinic receptor-mediated responses in relay cells and interneurons in the rat lateral geniculate nucleus.
Nicotinic receptor-mediated responses in relay cells and interneurons in the rat lateral geniculate nucleus.
复制标题
烟碱受体介导的大鼠外侧膝状核中继细胞和中间神经元的反应。
DOI：
10.1016/s0306-4522(97)00095-x
复制
发表时间：
1997
期刊：
影响因子：
3.3
通讯作者：
Uhlrich,DJ
中科院分区：
文献类型：
--
作者：
Zhu,JJ;Uhlrich,DJ
我们采用体外全细胞记录技术研究了成年大鼠外侧膝状体背侧核（将视觉信号从视网膜传递到皮层的丘脑核）中中继细胞和中间神经元的烟碱反应。这些膝状体中继细胞和中间神经元的生理和形态特征进行了鉴定。我们发现，在毒蕈碱拮抗剂阿托品的存在下，乙酰胆碱引起的中继细胞的去极化。应用尼古丁也可引起类似的去极化。这些去极化被烟碱拮抗剂，六甲双铵完全阻断，但几乎没有受到影响的浴溶液，含有河豚毒素和/或低钙浓度，以阻止突触传递。这表明去极化是由中继细胞中的烟碱受体直接介导的。尼古丁的应用也引起膝状体中间神经元的去极化。中间神经元继续表现出对尼古丁的反应，在突触阻滞的存在下，虽然反应的时间过程被改变。中继细胞和中间神经元的烟碱反应具有许多相似的性质。两者都表现出脱敏，尽管这种特征在中间神经元中更为明显。在这两种类型的细胞，烟碱反应激活了一个相对线性的电导轻微向内整流。电导的逆转电位约为− 33 mV，这与钠和钾离子的渗透性一致。当浴槽溶液含有低钙时，反转电位负移5- 6 mV，这进一步表明对钙离子的渗透性。我们的研究结果表明，烟碱受体存在于膝状体中继细胞和中间神经元。在中继细胞中的烟碱去极化可能有助于增强通过外侧膝状体核的视觉信号的传输，以及有助于膝状体中继细胞的反应模式从突发到强直（单棘波）放电的电压依赖性转变。中间神经元的烟碱去极化可能为胆碱能系统的激活可以增强外侧膝状体核的抑制性调谐的报道提供了一种解释。
We used the in vitro whole-cell recording technique to study the nicotinic responses of relay cells and interneurons in the adult rat dorsal lateral geniculate nucleus, the thalamic nucleus that conveys visual signals from the retina to the cortex. These geniculate relay cells and interneurons were identified by their physiological and morphological properties. We found that, in the presence of a muscarinic antagonist, atropine, acetylcholine induced a depolarization in relay cells. A similar depolarization was induced by application of nicotine. These depolarizations were completely blocked by a nicotinic antagonist, hexamethonium, but were little affected by bath solution that contained tetrodotoxin and/or low calcium concentration to block synaptic transmission. This suggests that the depolarization is mediated directly by nicotinic receptors in relay cells. Application of nicotine also induced a depolarization in geniculate interneurons. The interneurons continued to exhibit a response to nicotine in the presence of synaptic blockade, although the time-course of the response was altered. The nicotinic responses in relay cells and interneurons shared many similar properties. Both exhibited desensitization, although this characteristic was much more pronounced in the interneurons. In both cell types, the nicotinic response activated a relatively linear conductance with a slight inward rectification. The reversal potential for the conductance was about −33mV, which is consistent with a permeability to sodium and potassium ions. The reversal potential shifted negatively by 5–6mV when the bath solution contained low calcium, which further suggests a permeability to calcium ions. Our results indicate that nicotinic receptors are present in both geniculate relay cells and interneurons. The nicotinic depolarization in relay cells may serve to enhance transmission of visual signals through the lateral geniculate nucleus as well as to contribute to a voltage-dependent shift in the response mode of geniculate relay cells from burst to tonic (single-spike) firing. The nicotinic depolarization in interneurons may provide an explanation for reports that activation of the cholinergic system can enhance inhibitory tuning in the lateral geniculate nucleus.