We detected a diurnal change of vasoactive intestinal peptide (VIP) messenger RNA (mRNA) in the rat suprachiasmatic nucleus (SCN) using the in situ hybridization technique combined with computed image analysis. The amount of VIP mRNA was greatest at 02.00 h, the next largest level was seen at 20.00 h during the dark phase and smallest at 14.00 h during the light phase. We also confirmed that the onset of the fluctuation of mRNA occurred 2-6 h prior to the diurnal variation of the content of VIP-like immunoreactivity by semiquantitative immunocytochemistry. These findings suggest that light stimulus from the retina is a primarily influence on the transcription of VIP mRNA and induces a diurnal variation of VIP synthesis.
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)