The role of PACAP in the control of circadian expression of clock genes in the chicken pineal gland

Peptides. 2007 Sep;28(9):1767-74. doi: 10.1016/j.peptides.2007.07.013. Epub 2007 Jul 19.


Several features of the molecular circadian oscillator of the chicken pineal gland show homology with those in the mammalian SCN. Studies have shown the effects of PACAP on the mammalian SCN, but its effects on the expression of clock genes in the avian pineal gland have not yet been demonstrated. Clock and Cry1 expression was analyzed in pineal glands of chicken embryos after exposure to PACAP-38 in vitro. PACAP reduced expression of both clock genes within 2h. Ten hours after exposure, mRNA contents exceeded that of the controls. Our results support the hypothesis that the molecular clock machinery in the chicken pineal gland is also sensitive to PACAP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CLOCK Proteins
  • Chick Embryo
  • Chickens
  • Circadian Rhythm / genetics
  • Cryptochromes
  • Flavoproteins / genetics
  • Gene Expression Regulation, Developmental / drug effects
  • Pineal Gland / drug effects*
  • Pineal Gland / embryology
  • Pineal Gland / metabolism
  • Pituitary Adenylate Cyclase-Activating Polypeptide / pharmacology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Trans-Activators / genetics*


  • Cryptochromes
  • Flavoproteins
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • RNA, Messenger
  • Trans-Activators
  • CLOCK Proteins