Siberian hamsters free run or become arrhythmic after a phase delay of the photocycle.

Détails

ID Serval
serval:BIB_F5CF557BB075
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Siberian hamsters free run or become arrhythmic after a phase delay of the photocycle.
Périodique
American Journal of Physiology.
Auteur(s)
Ruby N.F., Saran A., Kang T., Franken P., Heller H.C.
ISSN
0002-9513
Statut éditorial
Publié
Date de publication
10/1996
Volume
271
Numéro
4
Pages
R881-R890
Langue
anglais
Résumé
Body temperature (Tb) and locomotor activity were recorded telemetrically from male Siberian hamsters (Phodopus sungorus sungorus) that were 3 or 12 mo of age and maintained in a light-dark (LD) cycle of 16 h light/day for 2-4 mo. After 3 wk of Tb recording, the LD cycle was phase delayed by extending the light phase by 5 h for 1 day; animals remained on a 16:8-h LD cycle for the remainder of the experiment. Tb and activity rhythms of all animals were stably entrained to the LD cycle before the phase shift. After the phase shift, > or = 80% of the animals in each age group failed to reentrain and expressed free-running Tb rhythms with stable periods that ranged from 24.33 to 26.33 h; one hamster in each age group reentrained within several days. Tb became arrhythmic in 10% of all animals immediately after, and in 28% of free running animals several weeks after, the phase shift. Changes in tau and phase of activity rhythms closely paralleled Tb rhythms in individual hamsters. Daily mean Tb was unchanged, but Tb rhythm amplitude decreased by 25-50% in individual animals after the phase shift. We believe this to be the first report of neurologically intact animals failing to reentrain to a phase shift of the LD cycle. These phenomena are not readily explained by current knowledge of circadian systems and suggest that the entrainment process in Siberian hamsters differs markedly from that in other rodent species.
Mots-clé
Animals, Body Temperature, Cricetinae, Male, Motor Activity, Periodicity, Phodopus, Photoperiod, Time Factors
Pubmed
Création de la notice
24/01/2008 16:31
Dernière modification de la notice
20/08/2019 17:22
Données d'usage