GnRH Neuron Firing and Response to GABA in Vitro Depend on Acute Brain Slice Thickness and Orientation
GnRH Neuron Firing and Response to GABA in Vitro Depend on Acute Brain Slice Thickness and Orientation
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DOI：
10.1210/en.2012-1126
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发表时间：
2012-08-01
期刊：
影响因子：
4.8
通讯作者：
Herbison, Allan E.
中科院分区：
文献类型：
--
作者：
Constantin, Stephanie;Piet, Richard;Herbison, Allan E.
GnRH神经元呈长树突状，并投射至正中隆起。本研究的目的是制作一种急性脑切片制备物，使记录能够从维持其树突或轴突完整范围的GnRH神经元进行。一个厚的，水平的大脑切片，它是可能的记录从水平取向的GnRH神经元位于下丘脑前区（AHA）。体内研究表明，大多数AHA GnRH神经元在GnRH激增时投射到血脑屏障外并表达c-Fos。On-cell记录比较了水平切片（AHAh）中的AHA GnRH神经元与冠状切片中的AHA和视前区（POA）GnRH神经元[分别为POA冠状（POAc）和AHA冠状（AHAc）]。AHAh GnRH神经元表现出更紧密的爆发式放电相比，其他切片方向。尽管α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）在所有制备物中都兴奋GnRH神经元，但γ-氨基丁酸（GABA）在AHAc和POAc中是兴奋性的，而在AHAh切片中是抑制性的。GABA（A）受体突触后电流在AHAh和AHAc脑片上相同。有趣的是，直接激活GABA（A）或GABA（B）受体分别刺激和抑制GnRH神经元，而与切片方向无关。随后的实验表明，GABA的净效应是由不同切片方向的GnRH神经元“长”和“短”树突中GABA（A）和GABA（B）受体介导效应的比例差异决定的。这些研究记录了一种新的脑切片制备，用于记录GnRH神经元及其广泛的树突/轴突，并强调了GnRH神经元定向相对于体外研究这些神经元时脑切片角度的重要性。（内分泌学153：3758-3769，2012）
The GnRH neurons exhibit long dendrites and project to the median eminence. The aim of the present study was to generate an acute brain slice preparation that enabled recordings to be undertaken from GnRH neurons maintaining the full extent of their dendrites or axons. A thick, horizontal brain slice was developed, in which it was possible to record from the horizontally oriented GnRH neurons located in the anterior hypothalamic area (AHA). In vivo studies showed that the majority of AHA GnRH neurons projected outside the blood-brain barrier and expressed c-Fos at the time of the GnRH surge. On-cell recordings compared AHA GnRH neurons in the horizontal slice (AHAh) with AHA and preoptic area (POA) GnRH neurons in coronal slices [POA coronal (POAc) and AHA coronal (AHAc), respectively]. AHAh GnRH neurons exhibited tighter burst firing compared with other slice orientations. Although alpha-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) excited GnRH neurons in all preparations, gamma-aminobutyric acid (GABA) was excitatory in AHAc and POAc but inhibitory in AHAh slices. GABA(A) receptor postsynaptic currents were the same in AHAh and AHAc slices. Intriguingly, direct activation of GABA(A) or GABA(B) receptors respectively stimulated and inhibited GnRH neurons regardless of slice orientation. Subsequent experiments indicated that net GABA effects were determined by differences in the ratio of GABA(A) and GABA(B) receptor-mediated effects in "long" and "short" dendrites of GnRH neurons in the different slice orientations. These studies document a new brain slice preparation for recording from GnRH neurons with their extensive dendrites/axons and highlight the importance of GnRH neuron orientation relative to the angle of brain slicing in studying these neurons in vitro. (Endocrinology 153: 3758-3769, 2012)