Corticotrophin-releasing factor augments the IH in rat hypothalamic paraventricular nucleus parvocellular neurons in vitro
Corticotrophin-releasing factor augments the IH in rat hypothalamic paraventricular nucleus parvocellular neurons in vitro
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DOI：
10.1152/jn.01325.2004
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发表时间：
2005-07-01
影响因子：
2.5
通讯作者：
Kannan, H
中科院分区：
文献类型：
--
作者：
Qiu, DL;Chu, CP;Kannan, H
本研究的目的是利用全细胞膜片钳记录和单细胞逆转录多重聚合酶链反应（单细胞 RT-mPCR）技术来表征促肾上腺皮质激素释放因子（CRF）对大鼠室旁核（PVN）假定的小细胞神经元的影响。在电流钳制下，CRF (10-600 nM) 增加神经元基础放电率，并以剂量依赖性方式使神经元去极化。 CRF 诱导的去极化不受 TTX、6-氰基-7-硝基喹喔啉-2 3-二酮 (CNQX) 和荷包牡丹碱共灌注的影响，但被 ZD7288 完全抑制。在电压钳下，300 nM CRF 以电压依赖性方式显着增加超极化激活的阳离子电流 (I-H)，将 I-H 电导-电压关系 (V-1/2) 向去极化方向移动约 7.8 mV，并在不改变斜率常数 (k) 的情况下增强 I-H 动力学。 ZD7288 的细胞外应用完全阻断 I-H 和 CRF 诱导的 I-H 增加。此外，细胞外应用 1 μM α-螺旋 CRF-(9-14) (α-hCRF)（一种非选择性 CRF 受体拮抗剂）可完全阻断 CRF 诱导的效应，但不受细胞外应用 antisauvagine-30（一种选择性 CRF 受体 2 拮抗剂）的影响。单细胞 RT-mPCR 分析显示这些神经元共表达 CRF 受体 1 mRNA 和 CRF 受体 2 mRNA。此外，CRF敏感神经元共表达HCN1通道mRNA、HCN2通道mRNA和HCN3通道mRNA，但不共表达HCN4通道mRNA。这些结果表明，CRF 通过 CRF 受体 1 介导的 HCN 离子通道活性增强来调节 PVN 小细胞神经元功能亚群。
The goal of this study was to characterize the effects of corticotrophin-releasing factor (CRF) on rat paraventricular nucleus (PVN) putative parvocellular neurons using whole cell patch-clamp recordings and single-cell reverse transcription-multiplex polymerase chain reaction (single-cell RT-mPCR) techniques. Under current clamp, CRF (10-600 nM) increased the neuronal basal firing rate and depolarized neurons in a dose-dependent manner. CRF-induced depolarization was unaffected by co-perfusion with TTX, 6-cyano-7-nitroquinoxaline-2 3-dione (CNQX), and bicuculline but was completely inhibited by ZD7288. Under voltage clamp, 300 nM CRF significantly increased the hyperpolarization-activated cation current (I-H) in a voltage-dependent manner, shifted the I-H conductance-voltage relationship (V-1/2) toward depolarization by similar to 7.8 mV, and enhanced the I-H kinetics without changing the slope constant (k). Extracellular application of ZD7288 completely blocked I-H and the CRF-induced increase in I-H. Furthermore, CRF-induced effects were completely blocked by extracellular application of 1 mu M alpha-helical CRF-(9-14) (alpha-hCRF), a nonselective CRF receptor antagonist, but were not affected by extracellular application of antisauvagine-30, a selective CRF-receptor 2 antagonist. Single-cell RT-mPCR analysis showed that these neurons co-expressed CRF receptor 1 mRNA and CRF receptor 2 mRNA. Furthermore, CRF-sensitive neurons co-expressed HCN1 channel mRNA, HCN2 channel mRNA, and HCN3 channel mRNA, but not HCN4 channel mRNA. These results suggest that CRF modulates the subpopulation of PVN parvocellular neuronal function by CRF-receptor 1-mediated potentiation of HCN ion channel activity.