Zheng Jijian, Lee Seunghoon, Zhou Z Jimmy
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
Nat Neurosci. 2006 Mar;9(3):363-71. doi: 10.1038/nn1644. Epub 2006 Feb 5.
Pharmacologically isolated starburst amacrine cells (SACs) in perinatal rabbit retinas spontaneously generated semiperiodic calcium spikes and long-lasting after-hyperpolarizations (AHPs), mediated by calcium-activated, cyclic AMP-sensitive potassium currents. These AHPs, rather than a depletion of neurotransmitters (as was previously believed), produced the refractory period of spontaneous retinal waves and set the upper limit of the wave frequency. Each SAC received inputs from roughly 10-30 neighboring SACs during a wave. These inputs synchronized and reshaped the intrinsic bursts to produce network oscillations at a rhythm different from that of individual SACs. With maturation, the semiperiodic bursts in SACs disappeared, owing to reduced intrinsic excitability and increased network inhibition. Thus, retinal waves are generated by a transient and specific network of cell-autonomous oscillators synchronized by reciprocally excitatory connections.
围产期兔视网膜中经药理学分离的星爆无长突细胞（SACs）自发产生半周期性钙峰和持久的超极化后电位（AHPs），这是由钙激活的、环磷酸腺苷敏感的钾电流介导的。这些超极化后电位而非神经递质耗竭（如之前所认为的）产生了自发视网膜波的不应期并设定了波频率的上限。在一次波期间，每个星爆无长突细胞接收来自大约10 - 30个相邻星爆无长突细胞的输入。这些输入使内在爆发同步并重塑，以产生与单个星爆无长突细胞不同节律的网络振荡。随着成熟，星爆无长突细胞中的半周期性爆发消失，这是由于内在兴奋性降低和网络抑制增加所致。因此，视网膜波由通过相互兴奋性连接同步的细胞自主振荡器的瞬态且特定的网络产生。
