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胆囊收缩素(CCK)是一种典型的脑肠肽,也是脑内含量最高的神经肽,具有神经递质或调质的作用,影响脑的多种功能活动,其中对痛觉的调制作用尤为人们重视.三叉脊束尾侧核(cNTST)是脊髓背角在延脑的延伸,含有CCK能纤维和受体,参与头面部特别是牙髓痛觉的调制和传递.本工作在大鼠离体脑片标本上,用细胞内记录技术研究CCK对cNTST神经元作用,旨在分析CCK的痛觉调制作用的可能机制.方法与文献[3]相似.70～120g的Wistar大鼠,断头后迅速取出脑干,用振动切片机将延脑尾端切成400μm厚的脑片,在人工脑脊液(CSF)中室温下孵育1h后进行实验.实验中CSF通以95%的O_2和5%的CO_2的混合气饱和,温度保持在32℃,灌流速度1～2mL/min.用灌充3mol/L乙酸钾的玻璃微电极在胞内记录,电极电阻80～160MΩ.CCK-8(Sigma)用蒸馏水配制成1mmol/L浓度的液体,灌入尖端直径10～20μm的微玻璃管内,经压力泵(PPS-2)注射.微玻璃管尖端放置在记录附近0.5mm内.实验共记录了32个神经元,膜电位为-50mV到-70mV.CCK-8使其中17个神经元产生去极化兴奋性反应,并呈剂量依赖性(图1),其余神经元无反应.用含1μmmol/L的河豚毒素(TTX)的CSF灌流脑片阻断突触传递后,CCK-8仍引起去极化反应(图2).
Cholecystokinin (CCK) is a typical brain gut peptide, is also the brain content of the highest neuropeptide, with neurotransmitters or the role of tempering, affecting the brain a variety of functional activities, of which modulation of pain is particularly the role of people (CNTST) is an extension of the spinal dorsal horn in the medulla oblongata and contains CCK fibers and receptors involved in the modulation and transmission of the pain in the facial area, especially in the pulpus.This study was performed in isolated rat brain CCK on cNTST neurons was studied by intracellular recording technique to analyze the possible mechanism of CCK pain modulation.Methods Wistar rats with the amplitude of 70 ~ 120g were similar to [3] .They were quickly removed after decapitation The brainstem was cut into 400μm thick brain slices by vibrating microtome and incubated for 1h at room temperature in artificial cerebrospinal fluid (CSF) with 95% O_2 and 5% CO_2 The gas mixture was saturated with a temperature of 32 ° C and a perfusion rate of 1 to 2 mL / min. Intracellular recording was performed with a glass microelectrode filled with 3 mol / L potassium acetate with electrode resistance of 80-160 MΩ. CCK-8 (Sigma) Into a 1mmol / L concentration of liquid, poured into the tip diameter of 10 ~ 20μm micro-glass tube, the pressure pump (PPS-2) The tip of the micro-glass tube was placed within 0.5mm near the record.A total of 32 neurons were recorded and the membrane potential was -50mV to -70mV.CKK-8 induced depolarization excitatory response in 17 of them In a dose-dependent manner (Figure 1), the remaining neurons were non-responsive and CCK-8 still caused a depolarization reaction after CSF blockade with 1 μmmol / L tetrodotoxin (TTX) ).