De Araujo Leonardo D, Roa Silvia L, Bueno Ana C, Coeli-Lacchini Fernanda B, Martins Clarissa S, Uchoa Ernane T, Antunes-Rodrigues Jose, Elias Lucila L, Elias Paula C, Moreira Ayrton C, De Castro Margaret
Department of Physiology, University of Sao Paulo Ribeirao Preto, Brazil.
Department of Internal Medicine, University of Sao Paulo Ribeirao Preto, Brazil.
Front Neurosci. 2016 Dec 6;10:567. doi: 10.3389/fnins.2016.00567. eCollection 2016.
Food access restriction is associated to changes in gene expression of the circadian clock system. However, there are only a few studies investigating the effects of non-photic synchronizers, such as food entrainment, on the expression of clock genes in the central oscillators. We hypothesized that different feeding restriction patterns could modulate the expression of clock genes in the suprachiasmatic nucleus (SCN) "master" clock and in extra-SCN oscillators such as the paraventricular (PVN) and arcuate (ARC) hypothalamic nuclei. rats were divided into four groups: Control group (CG; food available ), Restricted night-fed (RF-n; food access during 2 h at night), Restricted day-fed (RF-d; food access during 2 h at daytime), Day-fed (DF; food access during 12 h at daytime). After 21 days, rats were decapitated between ZT2-ZT3 (0800-0900 h); ZT11-ZT12 (1700-1800 h), or ZT17-18 (2300-2400 h). Plasma corticosterone was measured by radioimmunoassay (RIA). The expression of α, and α were assessed in SCN, PVN, and ARC hypothalamic nuclei by RT-PCR and calculated by the 2(2) method. Restricted food availability during few h led to decreased body weight in RF-n and RF-d groups compared to controls and DF group. We also observed an anticipatory corticosterone peak before food availability in RF-n and RF-d groups. Furthermore, the pattern of clock gene expression in response to RF-n, RF-d, and DF schedules was affected differently in the SCN, PVN, and ARC hypothalamic nuclei. In conclusion, the master oscillator in SCN as well as the oscillator in PVN and ARC, all brain areas involved in food intake, responds in a tissue-specific manner to feeding restriction.
食物获取受限与昼夜节律系统的基因表达变化有关。然而，仅有少数研究调查了非光同步器（如食物诱导）对中枢振荡器中时钟基因表达的影响。我们假设不同的进食限制模式可能会调节视交叉上核（SCN）“主”时钟以及室旁核（PVN）和弓状核（ARC）等SCN外振荡器中时钟基因的表达。将大鼠分为四组：对照组（CG；可获取食物）、夜间限制进食组（RF-n；夜间2小时可获取食物）、白天限制进食组（RF-d；白天2小时可获取食物）、白天进食组（DF；白天12小时可获取食物）。21天后，在ZT2-ZT3（08:00-09:00）、ZT11-ZT12（17:00-18:00）或ZT17-18（23:00-24:00）之间将大鼠断头。通过放射免疫分析（RIA）测量血浆皮质酮。通过RT-PCR评估SCN、PVN和ARC下丘脑核中α和α的表达，并通过2(2)方法计算。与对照组和DF组相比，RF-n组和RF-d组在数小时内食物供应受限导致体重下降。我们还在RF-n组和RF-d组中观察到在食物供应前有预期的皮质酮峰值。此外，SCN、PVN和ARC下丘脑核中对RF-n、RF-d和DF时间表的时钟基因表达模式受到不同影响。总之，SCN中的主振荡器以及PVN和ARC中的振荡器，这些参与食物摄入的所有脑区，对进食限制以组织特异性方式做出反应。
