Photoperiod effects on bombesin- and cholecystokinin-like immunoreactivity in the suprachiasmatic nuclei of the Djungarian hamster (Phodopus sungorus).
The immunocytochemical distribution of the putative satiety peptides bombesin (BBS) and cholecystokinin (CCK) were studied in the hypothalamic suprachiasmatic nuclei (SCN) of male and female Djungarian hamsters (Phodopus sungorus) held under either long (light/dark, LD 16:8 h) or short (LD 8:16) photoperiod. The animals were killed by perfusion with a fixative at the middle of the light period and the tissue was processed by routine immunohistochemical methods. Perikarya exhibiting BBS- or CCK-like immunoreactivity (LI) were found in the SCN of animals of all groups. Sex-related differences were not observed. In contrast, long-term exposure to short days decreased the number of neurons exhibiting CCK-LI dramatically when compared to long-day animals, while BBS-LI was not affected. The results suggest that CCK in the SCN is involved in the regulation of differential food intake in this highly photoperiodic rodent species.
Department of Anatomy, Johannes Gutenberg-University, Mainz, F.R.G.
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Reuss
D000818:Animals; D001839:Bombesin / Q000737:chemistry*; D002766:Cholecystokinin / Q000737:chemistry*; D006224:Cricetinae; D005260:Female; D007150:Immunohistochemistry; D008027:Light; D008297:Male; D010507:Periodicity; D013493:Suprachiasmatic Nucleus / Q000737:chemistry*; D013997:Time Factors; D014018:Tissue Distribution
D002766:Cholecystokinin; D001839:Bombesin