Regulation of Melatonin Production by Pineal Photoreceptor Cells: Role of Cyclic Nucleotides in the Trout (Oncorhynchus mykiss) Journal Article uri icon



  • Abstract: The light/dark cycle influences the rhythmic production of melatonin by the trout pineal organ through a modulation of the serotonin N‐acetyltransferase (NAT) activity. In static organ culture, cyclic AMP (cAMP) levels (in darkness) and NAT activity (in darkness or light) were stimulated in the presence of forskolin, isobutylmethylxanthine, or theophylline. Analogues of cAMP, but not of cyclic GMP, induced an increase in NAT activity. Light, applied after dark adaptation, inhibited NAT activity. This inhibitory effect was partially prevented in the presence of drugs stimulating cAMP accumulation. In addition, cAMP accumulation and NAT activity increase, induced by forskolin, were temperature dependent. Finally, melatonin release, determined in superfused organs under normal conditions of illumination, was stimulated during the light period of a light/dark cycle by adding an analogue of cAMP or a phosphodiesterase inhibitor. However, no further increase in melatonin release was observed during the dark phase of this cycle in the presence of the drugs. This report shows for the first time that cAMP is a candidate as intracellular second messenger participating in the control of NAT activity and melatonin production by light and temperature.

publication date

  • July 1, 1993

has restriction

  • closed

Date in CU Experts

  • January 22, 2014 9:42 AM

Full Author List

  • Thibault C; Falcón J; Greenhouse SS; Lowery CA; Gern WA; Collin J

author count

  • 6

Other Profiles

International Standard Serial Number (ISSN)

  • 0022-3042

Electronic International Standard Serial Number (EISSN)

  • 1471-4159

Additional Document Info

start page

  • 332

end page

  • 339


  • 61


  • 1