Fukuhara C, Inouye S I, Matsumoto Y, Tsujimoto G, Aoki K, Masuo Y
Life Science Institute, Sophia University, Tokyo, Japan.
Neurosci Lett. 1998 Jan 30;241(2-3):115-8. doi: 10.1016/s0304-3940(98)00041-x.
Pituitary adenylate cyclase-activating polypeptide (PACAP) was recently demonstrated to stimulate melatonin synthesis in the rat pineal gland. Circadian rhythms of melatonin concentration are well known. However, it has not been clarified whether PACAP contents in the pineal gland show circadian rhythm. In this study, we measured PACAP contents in the rat pineal gland throughout the day under 12:12 h light-dark cycle or constant dark conditions. A significant fluctuation was observed in the PACAP content under light-dark conditions but not under constant darkness. On the other hand, the pituitary gland showed no significant variation throughout the day under either conditions. These observations suggest that PACAP may participate in the modulation of melatonin synthesis depending on light conditions in the pineal gland.
垂体腺苷酸环化酶激活多肽（PACAP）最近被证明可刺激大鼠松果体中的褪黑素合成。褪黑素浓度的昼夜节律是众所周知的。然而，松果体中PACAP的含量是否呈现昼夜节律尚未明确。在本研究中，我们在12:12小时明暗循环或持续黑暗条件下，全天测量了大鼠松果体中的PACAP含量。在明暗条件下观察到PACAP含量有显著波动，但在持续黑暗条件下没有。另一方面，在这两种条件下，垂体全天均未显示出显著变化。这些观察结果表明，PACAP可能根据松果体中的光照条件参与褪黑素合成的调节。
