Klante G, Secci K, Masson-Pévet M, Pévet P, Vivien-Roels B, Steinlechner S, Wollnik F
Biological Institute, Department of Animal Physiology, University of Stuttgart, D-70550 Stuttgart, Germany.
Am J Physiol. 1999 Apr;276(4):R1078-86. doi: 10.1152/ajpregu.1999.276.4.R1078.
We investigated the possibility that strain-dependent differences in the diurnal pattern of wheel running activity rhythms are also reflected in the melatonin profiles. The inbred rat strains ACI/Ztm, BH/Ztm, and LEW/Ztm. LEW were examined for diurnal [12:12-h light-dark (LD)] wheel running activity, urinary 6-sulphatoxymelatonin (aMT6s) excretion, melatonin concentrations of plasma and pineal glands, and melatonin receptor density in the suprachiasmatic nuclei (SCN). ACI rats displayed unimodal activity patterns with a high level of activity, whereas BH and LEW rats showed multimodal activity patterns with ultradian components and reduced activity levels. In contrast, the individual daily profiles of aMT6s excretion and mean melatonin synthesis followed a unimodal time pattern in all three strains, suggesting that different output pathways of the SCN are responsible for the temporal organization of locomotor activity and pineal melatonin synthesis. In addition, melatonin synthesis at night and SCN melatonin receptor density at day were significantly higher in BH and LEW rats than in ACI rats. These results support the hypothesis of a long-term stimulating effect of melatonin on its own receptor density in the SCN.
我们研究了转轮活动节律的昼夜模式中品系依赖性差异也反映在褪黑素谱中的可能性。对近交系大鼠品系ACI/Ztm、BH/Ztm和LEW/Ztm. LEW进行了昼夜[12:12小时明暗（LD）]转轮活动、尿6-硫酸氧基褪黑素（aMT6s）排泄、血浆和松果体褪黑素浓度以及视交叉上核（SCN）中褪黑素受体密度的检测。ACI大鼠表现出具有高水平活动的单峰活动模式，而BH和LEW大鼠表现出具有超日成分和降低活动水平的多峰活动模式。相比之下，所有三个品系中aMT6s排泄的个体每日谱和平均褪黑素合成遵循单峰时间模式，这表明SCN的不同输出途径负责运动活动和松果体褪黑素合成的时间组织。此外，BH和LEW大鼠夜间的褪黑素合成和白天SCN的褪黑素受体密度显著高于ACI大鼠。这些结果支持了褪黑素对其自身在SCN中的受体密度具有长期刺激作用的假说。
