The relationship between circadian rhythmicity and vasoactive intestinal polypeptide in the suprachiasmatic nucleus of congenitally anophthalmic mice.
To date, the search for the clock component that is both necessary and sufficient for generation of circadian rhythms has relied primarily on experimental interventions such as lesions and transplantation of fetal SCN. While these approaches have been fruitful, lesions disrupt adjacent host tissue and fiber pathways, and donor tissue is likewise subject to trauma during harvest and transplantation. The current investigation has used congenitally anophthalmic (eyeless) mice to ask whether VIP-IR SCN neurons are necessary and sufficient for generation of circadian rhythms. In this animal model, arrhythmic mice occur naturally, together with their rhythmic littermates. We have combined recording of wheel-running activity with light microscopic immunocytochemistry for vasoactive intestinal polypeptide (VIP) and cytoarchitectural analysis of the suprachiasmatic nuclei (SCN) in rhythmic and arrhythmic anophthalmic mice. Our data provide the first definitive evidence that the presence of VIP neurons in the SCN is not sufficient for generation of circadian locomotor rhythms.
Laemle
L K
LK
Department of Anatomy, Cell Biology and Injury Sciences, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA. laemlelb@umdnj.edu
Ottenweller
J E
JE
D000818:Animals; D000853:Anophthalmos / Q000503:physiopathology*; D002940:Circadian Rhythm; D007150:Immunohistochemistry; D051379:Mice; D009043:Motor Activity; D009474:Neurons / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D014660:Vasoactive Intestinal Peptide