Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
PLoS One. 2013 Jul 10;8(7):e68243. doi: 10.1371/journal.pone.0068243. Print 2013.
Subterranean rodents spend most of the day inside underground tunnels, where there is little daily change in environmental variables. Our observations of tuco-tucos (Ctenomys aff. knighti) in a field enclosure indicated that these animals perceive the aboveground light-dark cycle by several bouts of light-exposure at irregular times during the light hours of the day. To assess whether such light-dark pattern acts as an entraining agent of the circadian clock, we first constructed in laboratory the Phase Response Curve for 1 h light-pulses (1000lux). Its shape is qualitatively similar to other curves reported in the literature and to our knowledge it is the first Phase Response Curve of a subterranean rodent. Computer simulations were performed with a non-linear limit-cycle oscillator subjected to a simple model of the light regimen experienced by tuco-tucos. Results showed that synchronization is achieved even by a simple regimen of a single daily light pulse scattered uniformly along the light hours of the day. Natural entrainment studies benefit from integrated laboratory, field and computational approaches.
穴居啮齿动物大部分时间都在地下隧道中度过，那里的环境变量每天几乎没有变化。我们对野外围栏中 tuco-tucos（Ctenomys aff. knighti）的观察表明，这些动物通过在白天的光照时间内不规则地多次暴露在光照下感知到地面上的光暗循环。为了评估这种明暗模式是否作为生物钟的同步因子，我们首先在实验室中构建了 1 小时光脉冲（1000lux）的相位反应曲线。其形状与文献中报道的其他曲线定性相似，据我们所知，这是第一个地下啮齿动物的相位反应曲线。我们用一个非线性极限环振荡器进行了计算机模拟，该振荡器受到 tuco-tucos 所经历的光照方案的简单模型的影响。结果表明，即使是每天仅一次的光脉冲均匀地散布在白天的光照时间内，也能实现同步。自然同步研究受益于综合的实验室、野外和计算方法。
