Light selectively alters vasoactive intestinal peptide and peptide histidine isoleucine immunoreactivity within the rat suprachiasmatic nucleus.
The concentration of vasoactive intestinal peptide (VIP)-, peptide histidine isoleucine (PHI)-, neurotensin (NT)- and substance P (SP)-like immunoreactivity (LI) within the suprachiasmatic nucleus (SCN) were determined by radioimmunoassay in rats housed in LD 14:10 h, constant light or constant dark. No day-night differences were observed in the concentration of VIP-, PHI-, NT- or SP-LI within the SCN. Exposure to constant light significantly depressed the SCN concentrations of VIP- and PHI-LI, but had no significant effects on SCN concentrations of NT- or SP-LI, or VIP- or PHI-LI concentrations within the cortex. These data represent the first evidence that VIP/PHI-containing neurons may be involved in mediating photic information within the SCN.
Department of Biology, Georgia State University, Atlanta 30303.
H E
HE
Albers
N
N
Minamitani
E
E
Stopa
C F
CF
Ferris
D000818:Animals; D003624:Darkness; D008027:Light; D008297:Male; D009994:Osmolar Concentration; D010451:Peptide PHI / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D013997:Time Factors; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D010451:Peptide PHI; D014660:Vasoactive Intestinal Peptide