Ben-Shlomo R, Nevo E, Ritte U, Steinlechner S, Klante G
Institute of Evolution, University of Haifa, Israel.
J Pineal Res. 1996 Nov;21(4):243-50. doi: 10.1111/j.1600-079x.1996.tb00293.x.
6-Sulphatoxymelatonin (aMT6S) excretion was examined in the urine of rhythmic and arrhythmic blind subterranean mole rats (Spalax ehrenbergi) to test the correlation between melatonin secretion (as represented by aMT6S) and variability in circadian locomotor activity. Activity pattern was tested in four males, first for a week under short photoperiod [light:dark (LD) 10:14], followed by 10 days in constant darkness (DD). After several months the experiment was repeated under long photoperiod (LD 14:10), followed by DD conditions. Under LD conditions all animals exhibited aMT6S excretion during the dark phase, with a decline just before the onset of light. No correlation was found between activity pattern and melatonin secretion. The animal with the highest melatonin secretion both under LD and DD had an arrhythmic locomotor pattern. The results suggest that in mole rats melatonin secretion and circadian locomotor activity are controlled by two different mechanisms. There were large differences in the aMT6S levels among individuals, suggesting the importance of duration of melatonin secretion over amplitude for gonadal development and thermoregulatory changes. During summer, i.e., before the breeding season, the animals keep a more stable aMT6S secretion than in winter, and the amplitude of secretion is higher under DD vs. LD conditions.
检测了节律性和无节律性的盲鼹形鼠（斯氏鼹鼠）尿液中的6-硫酸氧褪黑素（aMT6S）排泄情况，以测试褪黑素分泌（以aMT6S表示）与昼夜运动活动变异性之间的相关性。对四只雄性鼹鼠的活动模式进行了测试，首先在短光照周期[光照：黑暗（LD）10:14]下测试一周，然后在持续黑暗（DD）中测试10天。几个月后，在长光照周期（LD 14:10）下重复实验，随后是DD条件。在LD条件下，所有动物在黑暗阶段均表现出aMT6S排泄，在光照开始前排泄量下降。未发现活动模式与褪黑素分泌之间存在相关性。在LD和DD条件下褪黑素分泌最高的动物具有无节律的运动模式。结果表明，在鼹形鼠中，褪黑素分泌和昼夜运动活动受两种不同机制控制。个体之间的aMT6S水平存在很大差异，这表明褪黑素分泌持续时间而非幅度对性腺发育和体温调节变化更为重要。在夏季，即繁殖季节之前，动物的aMT6S分泌比冬季更稳定，并且在DD条件下与LD条件下相比，分泌幅度更高。
