Twice daily melatonin peaks in Siberian but not Syrian hamsters under 24 h light:dark:light:dark cycles.
Twice daily melatonin peaks in Siberian but not Syrian hamsters under 24 h light:dark:light:dark cycles.
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西伯利亚人的褪黑激素每天两次，但在24小时以下的叙利亚仓鼠中峰值峰值：黑暗：光：黑暗循环。
DOI：
10.3109/07420528.2012.719965
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发表时间：
2012-11
影响因子：
2.8
通讯作者：
Gorman MR
中科院分区：
文献类型：
--
作者：
Raiewski EE;Elliott JA;Evans JA;Glickman GL;Gorman MR
在多振荡器昼夜节律起搏器的控制下，血源褪黑素的每日模式随季节变化。在这里，我们研究了西伯利亚和叙利亚仓鼠在双峰LDLD8:4:8:4和LD20:4照明时间表下褪黑激素分泌和运动活动的模式，这些时间表促进了组成昼夜节律振荡器的新时间安排。在LDLD条件下，两种植物的轮跑活动在不同的白天和夜间分岔。西伯利亚仓鼠在LDLD的每个斑期以及LD20:4的单个日斑期均显示出显著的褪黑素增加。褪黑素的双峰分泌模式在急性延长的16 h期持续存在。相比之下，叙利亚仓鼠在LDLD8:4:8:4或ldld20:4均未显示血浆褪黑素显著增加。在这个物种中，只有当LDLD的白昼期急剧延长到产生16小时的黑暗时，才观察到可检测的水平。已确定的物种夜间褪黑激素分泌相对于活动开始的相位滞后差异可能是上述对比的基础：在24小时LD周期中，西伯利亚仓鼠在活动开始后约2小时内褪黑激素分泌增加，而叙利亚仓鼠在活动开始和L/D转换后至少4小时可检测到褪黑激素分泌阶段。目前的研究结果提供了新的证据，表明褪黑激素分泌波形的多振荡器调节，特别是夜间分泌的开始、偏移和持续时间的昼夜节律控制。
The daily pattern of blood borne melatonin varies seasonally under the control of a multi-oscillator circadian pacemaker. Here we examine patterns of melatonin secretion and locomotor activity in Siberian and Syrian hamsters entrained to bimodal LDLD8:4:8:4 and LD20:4 lighting schedules that facilitate novel temporal arrangements of component circadian oscillators. Under LDLD, both species robustly bifurcated wheel-running activity in distinct day scotophase (DS) and night scotophase (NS) bouts. Siberian hamsters displayed significant melatonin increases during each scotophase in LDLD, and in the single daily scotophase of LD20:4. The bimodal melatonin secretion pattern persisted in acutely extended 16 h scotophases. Syrian hamsters, in contrast, showed no significant increases in plasma melatonin during either scotophase of LDLD8:4:8:4 or in LD20:4. In this species, detectable levels were observed only when the day scotophase of LDLD was acutely extended to yield 16 h of darkness. Established species differences in the phase lag of nocturnal melatonin secretion relative to activity onset may underlie the above contrast: In non-bifurcated entrainment to 24 h LD cycles, Siberian hamsters show increased melatonin secretion within ~ 2 h after activity onset, whereas in Syrian hamsters, detectable melatonin secretion phase lags activity onset and the L/D transition by at least 4 h. The present results provide new evidence indicating multi-oscillator regulation of the waveform of melatonin secretion, specifically, the circadian control of the onset, offset, and duration of nocturnal secretion.