Faluhelyi Nándor, Reglodi Dóra, Lengvári István, Csernus Valér
Department of Anatomy, University of Pécs Medical School, and Neurohumoral Regulations Research Group of the Hungarian Academy of Sciences, Szigeti u 12, Pécs 7624, Hungary.
Regul Pept. 2004 Dec 15;123(1-3):23-8. doi: 10.1016/j.regpep.2004.05.009.
Pituitary adenylate cyclase activating polypeptide (PACAP) has been shown to participate in modulation of circadian rhythm and to stimulate melatonin (MT) secretion in both the rat and chicken pineal glands. In contrast to mammals, the main regulator of circadian rhythm in birds is the pineal gland, which begins its rhythmic MT production already during embryonic life. In the present study, we investigated the development of MT secretion in explanted embryonic chicken pineals and their responsiveness to PACAP in a perifusion system. Our results show that: (1) the circadian clock and/or the intracellular signal transduction system connecting the clock to MT synthesizing apparatus develop between the embryonic days 16-18 (E16-18), even in vitro. (2) Exposure of the embryonic chicken pineal gland to PACAP induces transitory increase in MT secretion but does not induce visible phase shift in the circadian rhythm. (3) Cyclic AMP (cAMP) efflux also responds to PACAP at or before day E13 in embryonic chicken pineal gland in vitro.
垂体腺苷酸环化酶激活多肽（PACAP）已被证明参与昼夜节律的调节，并刺激大鼠和鸡松果体中的褪黑素（MT）分泌。与哺乳动物不同，鸟类昼夜节律的主要调节者是松果体，它在胚胎期就开始有节律地分泌MT。在本研究中，我们研究了体外培养的胚胎鸡松果体中MT分泌的发育情况及其对PACAP的反应。我们的结果表明：（1）即使在体外，昼夜节律钟和/或将生物钟与MT合成装置相连的细胞内信号转导系统在胚胎第16 - 18天（E16 - 18）之间发育。（2）胚胎鸡松果体暴露于PACAP会导致MT分泌短暂增加，但不会引起昼夜节律的明显相移。（3）体外培养的胚胎鸡松果体在E13天或之前，环磷酸腺苷（cAMP）外流也对PACAP有反应。
