Shinohara K, Hiruma H, Funabashi T, Kimura F
Department of Physiology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan.
Neuroscience. 2000;96(3):591-6. doi: 10.1016/s0306-4522(99)00556-4.
We employed morphological and electrophysiological methods in order to elucidate mechanisms which are responsible for communication between cellular oscillators in the cultured rat suprachiasmatic nucleus, the site of the endogenous biological clock that regulates circadian rhythms in mammals. When a gap junction-permeable dye, Lucifer Yellow, was injected into single neurons in the suprachiasmatic nucleus culture, the dye was transferred to neighboring cells in a gap junction blocker-sensitive manner. Optical imaging of neural activity evoked by electrical stimulation in the culture revealed that the spread of depolarization was inhibited by gap junction blockers but not by a blocker of voltage-dependent Na(+) channels. Depolarization propagation was inhibited by muscimol, a GABA(A) receptor agonist, in a dose-dependent manner and the inhibition was reversed by bicuculline, a GABA(A) receptor antagonist. Furthermore, muscimol inhibited dye-transfer between neurons in the suprachiasmatic nucleus culture in a dose-dependent fashion.These independent lines of evidence suggest that the gap junction communication is involved in interneuronal communication in the suprachiasmatic nucleus slice culture and that the coupling state between neurons is not static but dynamically regulated via GABA(A) receptor systems.
我们采用形态学和电生理学方法，以阐明负责培养的大鼠视交叉上核（哺乳动物内源性生物钟调节昼夜节律的部位）中细胞振荡器之间通讯的机制。当将一种可透过缝隙连接的染料鲁米诺黄注入视交叉上核培养物中的单个神经元时，染料以对缝隙连接阻滞剂敏感的方式转移到相邻细胞。对培养物中电刺激诱发的神经活动进行光学成像显示，去极化的传播受到缝隙连接阻滞剂的抑制，但不受电压依赖性钠通道阻滞剂的抑制。GABA(A)受体激动剂蝇蕈醇以剂量依赖性方式抑制去极化传播，而GABA(A)受体拮抗剂荷包牡丹碱可逆转这种抑制作用。此外，蝇蕈醇以剂量依赖性方式抑制视交叉上核培养物中神经元之间的染料转移。这些独立的证据表明，缝隙连接通讯参与视交叉上核切片培养中的神经元间通讯，并且神经元之间的耦合状态不是静态的，而是通过GABA(A)受体系统动态调节的。
