Aguilar-Roblero R, Vega-González A
Departamento de Neurociencias, Universidad Nacional Autonoma de México, DF.
Brain Res. 1993 Mar 12;605(2):229-36. doi: 10.1016/0006-8993(93)91745-e.
The role of the pineal gland in the mammalian circadian system has not been well established, in contrast to a fair number of reports indicating pharmacological effects of melatonin in the circadian organization. In order to establish the effects of pinealectomy on the time course of splitting of circadian rhythmicity, the wheel running locomotor activity was continuously recorded in golden hamsters under light-dark conditions or constant light. The analysis of transients from the actograms shows that removal of the pineal gland induces a reduction in the latency and an increase in the duration of transients before the splitting occurs. The power spectral analysis from selected segments of the data shows that concomitant to the development of the splitting there is an increase in the power of ultradian components. In pinealectomized animals the changes in the power spectrum occurs at least 30 days before that in the control animals. These observations suggest that pineal gland could be involved in the coupling mechanism among the different oscillators of the rodent circadian system. Furthermore, since the light intensity used in this study is enough to completely suppress the melatonin synthesis from the pineal, the present results suggest that a signal from the pineal other than melatonin is involved in the process.
与大量表明褪黑素在昼夜节律组织中具有药理作用的报告相反，松果体在哺乳动物昼夜节律系统中的作用尚未得到充分证实。为了确定松果体切除对昼夜节律分裂时间进程的影响，在明暗条件或持续光照下，连续记录金黄仓鼠的转轮运动活动。对活动记录图中的瞬变进行分析表明，切除松果体可导致分裂发生前瞬变的潜伏期缩短和持续时间延长。对选定数据段进行的功率谱分析表明，随着分裂的发展，超日分量的功率增加。在松果体切除的动物中，功率谱的变化比对照动物至少提前30天出现。这些观察结果表明，松果体可能参与啮齿动物昼夜节律系统不同振荡器之间的耦合机制。此外，由于本研究中使用的光照强度足以完全抑制松果体合成褪黑素，目前的结果表明，除褪黑素外，来自松果体的另一种信号也参与了这一过程。
