Suprachiasmatic nucleus neurons are glucose sensitive
Suprachiasmatic nucleus neurons are glucose sensitive
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DOI：
10.1177/074873049701200501
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发表时间：
1997-10-01
影响因子：
3.5
通讯作者：
Bickar, D
中科院分区：
文献类型：
--
作者：
Hall, AC;Hoffmaster, RM;Bickar, D
下丘脑的视交叉上核（SCN）是哺乳动物昼夜节律的起搏器。在仓鼠脑切片制备中，作者能够在体外记录SCN细胞长达4天的自发活动，并验证放电的自我维持节律。该节律的相位被浴液中的葡萄糖浓度改变，对于20 mM葡萄糖条件，峰值激发时间提前，而对于5 mM葡萄糖条件，峰值激发时间略微延迟，在将浸浴介质变回10 mM后，在体外第2天期间，20 mM葡萄糖的提前效果和5 mM葡萄糖的延迟效果没有保持葡萄糖，因此表明该效应不是潜在振荡的永久相移。在从急性分离的仓鼠SCN神经元上的细胞附着的膜贴片记录的实验中，将沐浴培养基从高（20 mM）交换到零葡萄糖增加了钾（K+）选择性通道活性。作者揭示了存在一个格列本脲敏感的K+通道（190 pS）和一个更大的电导（260 pS）的Ca2+依赖性K+通道，在细胞质表面ATP都可逆抑制的通道。此外，证明ImM四乙基氯化铵以与高浓度葡萄糖（20mM）类似的方式提前脑切片中的峰值发射时间。作者将结果解释为暗示SCN对葡萄糖敏感，最可能是通过ATP调节这些神经元中的K+通道活性。K+通道活动的紧张性调制似乎改变起搏器的输出，但不重置相位。
The suprachiasmatic nucleus (SCN) in the hypothalamus serves as the pacemaker for mammalian circadian rhythms. In a hamster brain slice preparation, the authors were able to record spontaneous activity from SCN cells for up to 4 days in vitro and verify a self-sustained rhythm in firing. The phase of this rhythm was altered by the concentration of glucose in the bathing medium, with time of peak firing advanced for a 20 mM glucose condition and slightly delayed for a 5 mM glucose condition, relative to 10 mM. The advancing effect of 20 mM glucose and the delaying effect of 5 mM glucose were not maintained during a 2nd day in vitro after changing the bathing medium back to 10 mM glucose, thus indicating the effect was not a permanent phase shift of the underlying oscillation. In experiments recording from cell-attached membrane patches on acutely dissociated hamster SCN neurons, exchanging the bathing medium from high (20 mM) to zero glucose increased potassium (K+)-selective channel activity With inside-out membrane patches, the authors revealed the presence of a glybenclamide-sensitive K+ channel(190 pS) and a larger conductance (260 pS) Ca2+-dependent K+ channel that were both reversibly inhibited by ATP at the cytoplasmic surface. Furthermore, 1 mM tetraethylammonium chloride was demonstrated to advance peak firing time in the brain slice in a similar manner to a high concentration of glucose (20 mM). The authors interpret the results to imply that SCNs are sensitive to glucose, most probably via ATP modulation of K+ channel activity in these neurons. Tonic modulation of K+ channel activity appears to alter output of the pacemaker but does not reset the phase.