Zhao Z Y, Touitou Y
Biochemical Department, Faculté de Médecine Pitié-Salpêtrière, Paris, France.
J Pineal Res. 1993 Mar;14(2):73-7. doi: 10.1111/j.1600-079x.1993.tb00488.x.
Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/l) and magnesium (1.34 mmol/l) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/l) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.
鉴于可能存在的昼夜节律阶段依赖性，我们在此记录了松果体褪黑素分泌对已知对松果体功能有效的电解质的反应。我们研究了在对应于光照期和黑暗期中间的两个不同昼夜节律阶段，即分别为光照开始后7小时和19小时（光：暗 = 12:12），经体外灌流的大鼠松果体中褪黑素的释放情况。正如预期的那样，从在黑暗期处死的大鼠身上取出的腺体灌流液中的初始流出率，比从光照期处死的大鼠身上取出的腺体灌流液中的初始流出率要高得多。灌流3小时后，无论昼夜节律阶段如何，褪黑素释放达到相似水平，并在灌流至第8小时时保持恒定。用大鼠生理浓度的钙（5.2 mmol/L）和镁（1.34 mmol/L）对腺体进行灌流，对从在黑暗期中间（19 HALO）处死的大鼠身上取出的松果体有刺激作用，而对从光照期（7 HALO）处死的大鼠身上取出的松果体未观察到影响。锂（0.28和0.55 mmol/L）对在7 HALO和19 HALO取出的松果体中褪黑素的释放无作用。我们的结果表明，根据昼夜节律阶段，褪黑素的初始流出率以及体外灌流的松果体对钙和镁的反应存在差异。
