Abstract：
Corticotropin-releasing factor (CRF) is the major neuromodulator orchestrating the stress response, and is secreted by neurons in various regions of the brain. Cerebellar CRF is released by afferents from inferior olivary neurons and other brainstem nuclei in response to stressful challenges, and contributes to modulation of synaptic plasticity and motor learning behavior via its receptors. We recently found that CRF modulates facial stimulation-evoked molecular layer interneuron-Purkinje cell (MLI-PC) synaptic transmission via CRF type 1 receptor (CRF-R1) in vivo in mice, suggesting that CRF modulates sensory stimulation-evoked MLI-PC synaptic plasticity. However, the mechanism of how CRF modulates MLI-PC synaptic plasticity is unclear. We investigated the effect of CRF on facial stimulation-evoked MLI-PC long-term depression (LTD) in urethane-anesthetized mice by cell-attached recording technique and pharmacological methods.
Facial stimulation at 1 Hz induced LTD of MLI-PC synaptic transmission under control conditions, but not in the presence of CRF (100 nM). The CRF-abolished MLI-PC LTD was restored by application of a selective CRF-R1 antagonist, BMS-763,534 (200 nM), but it was not restored by application of a selective CRF-R2 antagonist, antisauvagine-30 (200 nM). Blocking cannabinoid type 1 (CB1) receptor abolished the facial stimulation-induced MLI-PC LTD, and revealed a CRF-triggered MLI-PC long-term potentiation (LTP) via CRF-R1. Notably, either inhibition of protein kinase C (PKC) with chelerythrine (5 µM) or depletion of intracellular Ca2+ with cyclopiazonic acid (100 µM), completely prevented CRF-triggered MLI-PC LTP in mouse cerebellar cortex in vivo.
The present results indicated that CRF blocked sensory stimulation-induced opioid-dependent MLI-PC LTD by triggering MLI-PC LTP through CRF-R1/PKC and intracellular Ca2+ signaling pathway in mouse cerebellar cortex. These results suggest that activation of CRF-R1 opposes opioid-mediated cerebellar MLI-PC plasticity in vivo in mice.
Facial stimulation at 1 Hz induced LTD of MLI-PC synaptic transmission under control conditions, but not in the presence of CRF (100 nM). The CRF-abolished MLI-PC LTD was restored by application of a selective CRF-R1 antagonist, BMS-763,534 (200 nM), but it was not restored by application of a selective CRF-R2 antagonist, antisauvagine-30 (200 nM). Blocking cannabinoid type 1 (CB1) receptor abolished the facial stimulation-induced MLI-PC LTD, and revealed a CRF-triggered MLI-PC long-term potentiation (LTP) via CRF-R1. Notably, either inhibition of protein kinase C (PKC) with chelerythrine (5 µM) or depletion of intracellular Ca2+ with cyclopiazonic acid (100 µM), completely prevented CRF-triggered MLI-PC LTP in mouse cerebellar cortex in vivo.
The present results indicated that CRF blocked sensory stimulation-induced opioid-dependent MLI-PC LTD by triggering MLI-PC LTP through CRF-R1/PKC and intracellular Ca2+ signaling pathway in mouse cerebellar cortex. These results suggest that activation of CRF-R1 opposes opioid-mediated cerebellar MLI-PC plasticity in vivo in mice.
摘要：
促肾上腺皮质激素释放因子(CRF)是调节应激反应的主要神经调质,并由大脑各个区域的神经元分泌。小脑CRF通过下橄榄神经元和其他脑干核的传入释放，以应对紧张的挑战。并有助于通过其受体调节突触可塑性和运动学习行为。我们最近发现CRF在小鼠体内通过CRF1型受体（CRF-R1）调节面部刺激诱发的分子层中间神经元-浦肯野细胞（MLI-PC）突触传递，提示CRF调节感觉刺激诱发的MLI-PC突触可塑性。然而,CRF如何调节MLI-PC突触可塑性的机制尚不清楚.我们通过细胞附着记录技术和药理学方法研究了CRF对氨基甲酸乙酯麻醉小鼠面部刺激诱发的MLI-PC长期抑郁症（LTD）的影响。
在控制条件下，1Hz的面部刺激诱导了MLI-PC突触传递的LTD，但不存在CRF（100nM）。通过应用选择性CRF-R1拮抗剂恢复了CRF废除的MLI-PCLTD，BMS-763,534(200nM),但它并没有通过应用选择性CRF-R2拮抗剂来恢复，antisauvagine-30(200nM)。阻断大麻素1型（CB1）受体消除了面部刺激诱导的MLI-PCLTD，并通过CRF-R1揭示了CRF触发的MLI-PC长期增强（LTP）。值得注意的是,用白屈菜红碱（5µM）抑制蛋白激酶C（PKC）或用环吡嗪酸（100µM）消耗细胞内Ca2，完全阻止CRF触发的MLI-PCLTP在小鼠小脑皮层的体内。
目前的结果表明，CRF通过CRF-R1/PKC和细胞内Ca2信号通路触发MLI-PCLTP，阻断了感觉刺激诱导的阿片依赖性MLI-PCLTD。这些结果表明，CRF-R1的激活在小鼠体内对抗阿片样物质介导的小脑MLI-PC可塑性。
在控制条件下，1Hz的面部刺激诱导了MLI-PC突触传递的LTD，但不存在CRF（100nM）。通过应用选择性CRF-R1拮抗剂恢复了CRF废除的MLI-PCLTD，BMS-763,534(200nM),但它并没有通过应用选择性CRF-R2拮抗剂来恢复，antisauvagine-30(200nM)。阻断大麻素1型（CB1）受体消除了面部刺激诱导的MLI-PCLTD，并通过CRF-R1揭示了CRF触发的MLI-PC长期增强（LTP）。值得注意的是,用白屈菜红碱（5µM）抑制蛋白激酶C（PKC）或用环吡嗪酸（100µM）消耗细胞内Ca2，完全阻止CRF触发的MLI-PCLTP在小鼠小脑皮层的体内。
目前的结果表明，CRF通过CRF-R1/PKC和细胞内Ca2信号通路触发MLI-PCLTP，阻断了感觉刺激诱导的阿片依赖性MLI-PCLTD。这些结果表明，CRF-R1的激活在小鼠体内对抗阿片样物质介导的小脑MLI-PC可塑性。
