Cholecystokinin activates orexin/hypocretin neurons through the cholecystokinin A receptor
Cholecystokinin activates orexin/hypocretin neurons through the cholecystokinin A receptor
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DOI：
10.1523/jneurosci.1193-05.2005
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发表时间：
2005-08-10
影响因子：
5.3
通讯作者：
Sakurai, T
中科院分区：
文献类型：
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作者：
Tsujino, N;Yamanaka, A;Sakurai, T
食欲素A和B是参与调节睡眠/觉醒和能量稳态的神经肽。食欲素神经元活动的调控机制尚不清楚。利用食欲素神经元特异性表达黄骆驼蛋白2.1的转基因小鼠，我们筛选了影响食欲素神经元活性的因素（共检测了21个多肽和6个其他因素），发现一种硫酸化的八肽形式的胆囊收缩素（CCK-8S）、神经紧张素、催产素和加压素可以激活食欲素神经元。通过钙显像和片钳记录研究cck - 8s诱导食欲素神经元活化的机制。CCK-8S诱导食欲素神经元向内电流。CCKA受体拮抗剂洛格鲁胺抑制cck - 8s诱导的食欲素神经元的激活，而CCKB受体激动剂CCK-4（一种四肽形式的胆囊收缩素）和非磺化的CCK-8作用不大。cck - 8s诱导的细胞内钙浓度升高可以通过去除细胞外钙来消除，但不能通过添加thapsigargin来消除。硝苯地平、omega- concontoxin、omega-agatoxin、4-乙基苯基氨基-1,2-二甲基-6-甲基氨基吡啶氯化铵和SNX-482对cck - 8s诱导的钙内流影响不大，但La3+、Gd3+和2-氨基乙氧基二苯硼酸盐抑制cck - 8s诱导的钙内流。此外，cck - 8s诱导的内向电流在无钙溶液中显著增强，并被阳离子通道阻滞剂SKF96365抑制，这表明细胞外钙敏感阳离子通道参与其中。当膜电位固定在-60 mV时，CCK-8S未引起细胞内钙浓度的增加，提示钙的增加是由去极化引起的。本文提出的证据扩展了我们对食欲素神经元的调节和CCK在中枢神经系统中的生理作用的理解。
Orexin A and B are neuropeptides implicated in the regulation of sleep/wakefulness and energy homeostasis. The regulatory mechanism of the activity of orexin neurons is not precisely understood. Using transgenic mice in which orexin neurons specifically express yellow cameleon 2.1, we screened for factors that affect the activity of orexin neurons (a total of 21 peptides and six other factors were examined) and found that a sulfated octapeptide form of cholecystokinin (CCK-8S), neurotensin, oxytocin, and vasopressin activate orexin neurons. The mechanisms that underlie CCK-8S-induced activation of orexin neurons were studied by both calcium imaging and slice patch-clamp recording. CCK-8S induced inward current in the orexin neurons. The CCKA receptor antagonist lorglumide inhibited CCK-8S-induced activation of orexin neurons, whereas the CCKB receptor agonists CCK-4 (a tetrapeptide form of cholecystokinin) and nonsulfated CCK-8 had little effect. The CCK-8S-induced increase in intracellular calcium concentration was eliminated by removing extracellular calcium but not by an addition of thapsigargin. Nifedipine, omega-conotoxin, omega-agatoxin, 4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidinium chloride, and SNX-482 had little effect, but La3+, Gd3+, and 2-aminoethoxydiphenylborate inhibited CCK-8S-induced calcium influx. Additionally, the CCK-8S-induced inward current was dramatically enhanced in the calcium-free solution and was inhibited by the cation channel blocker SKF96365, suggesting an involvement of extracellular calcium-sensitive cation channels. CCK-8S did not induce an increase in intracellular calcium concentration when membrane potential was clamped at -60 mV, suggesting that the calcium increase is induced by depolarization. The evidence presented here expands our understanding of the regulation of orexin neurons and the physiological role of CCK in the CNS.