caa a22 4500 47584548X CHVBK 20180406123913.0 cr unu---uuuuu 170329e20001101xx s 000 0 eng 10.1007/PL00000658 doi (NATIONALLICENCE)springer-10.1007/PL00000658 Single-cell recordings from chick pineal glands in vitro reveal ultradian and circadian oscillations [Elektronische Daten] [J. Schenda, L. Vollrath*] Abstract.: Evidence is clear that each melatonin-producing cell in the chick pineal gland contains a circadian oscillator that continues to function in vitro, resulting in a prominent day/night rhythm of melatonin secretion. The aim of the present investigation was to examine whether the circadian organization of the gland has an electrophysiological correlate. To this end, single-cell recordings were made from isolated chick pineal glands kept in vitro under a light/dark cycle of 12:12 h, identical to that of the donors, or under continuous light or darkness. In all the glands investigated, a very small percentage of cells exhibited sodium-dependent spontaneous spike activity with a mean frequency below 10 Hz. The cells revealed rhythms with periods in the 15- to 60-min range and, additionally, exhibited ultradian and circadian rhythms in firing, with periods of 10.75 ± 1.06 h and 26.25 ± 1.26 h (mean ± standard deviation), respectively. Most of the cells exhibited circadian rhythms with higher activity during daytime than at night, showing that the electrical activity and melatonin rhythm were out of phase. Under constant light or darkness, the circadian rhythm persisted. When the light/dark cycle of the donors was phase-advanced by 5 h, the cells revealed complete entrainment. We discuss whether the cells, albeit small in number, could function as a secondary ultradian/circadian oscillator contributing to the ultradian/circadian organization of the gland. Birkhäuser Verlag Basel,, 2000 Key words. Pineal gland nationallicence chick nationallicence electrical activity nationallicence chronobiology nationallicence circadian rhythm nationallicence Schenda J. Institute of Anatomy, Johannes Gutenberg-University, D-55099 Mainz (Germany), Fax +49 6131 39 23 719, e-mail: vollrath@mail.uni-mainz.de, DE aut Vollrath* L. Institute of Anatomy, Johannes Gutenberg-University, D-55099 Mainz (Germany), Fax +49 6131 39 23 719, e-mail: vollrath@mail.uni-mainz.de, DE aut https://doi.org/10.1007/PL00000658 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/PL00000658 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schenda J. Institute of Anatomy, Johannes Gutenberg-University, D-55099 Mainz (Germany), Fax +49 6131 39 23 719, e-mail: vollrath@mail.uni-mainz.de, DE aut NATIONALLICENCE 700 1- Vollrath* L. Institute of Anatomy, Johannes Gutenberg-University, D-55099 Mainz (Germany), Fax +49 6131 39 23 719, e-mail: vollrath@mail.uni-mainz.de, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer