AJP - Regu Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 271: R813-R818, 1996;
0363-6119/96 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Boulos, Z.
Right arrow Articles by Terman, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Boulos, Z.
Right arrow Articles by Terman, M.

AJP - Regulatory, Integrative and Comparative Physiology, Vol 271, Issue 3 813-R818, Copyright © 1996 by American Physiological Society

ARTICLES

Twilight transitions promote circadian entrainment to lengthening light-dark cycles

Z. Boulos, M. Macchi and M. Terman
Institute for Circadian Physiology, Cambridge, Massachusetts 02140, USA.

The upper limits of entrainment of the circadian activity rhythm were compared in hamsters initially exposed to daily light-dark (LD) cycles with either abrupt (LD-rectangular) or simulated twilight (LD-twilight) transitions. Daytime illuminance (10 lx) and the total amount of light emitted per day were the same under the two LD cycles. One-half of the animals in each condition had access to dark nest boxes. The period of the LD cycles was then increased from 24 to 26 h, by 5 min per day. All animals in LD-twilight remained entrained to the lengthening cycle, whereas 60% of those in LD-rectangular began to free run well before the period of the cycle reached 26 h. These effects were independent of nest box availability. The lengthening LD cycles exerted clear aftereffects on the period of the rhythms in constant darkness, the magnitude of which was related to the efficacy of prior entrainment. The results indicate that twilight transitions raise the upper limit of entrainment to LD cycles, suggesting that their inclusion increases the strength of the LD zeitgeber.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
J. J. Chiesa, M. Angles-Pujolras, A. Diez-Noguera, and T. Cambras
Activity rhythm of golden hamster (Mesocricetus auratus) can be entrained to a 19-h light-dark cycle
Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2005; 289(4): R998 - R1005.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
M. Jác, A. Sumova, and H. Illnerova
c-Fos rhythm in subdivisions of the rat suprachiasmatic nucleus under artificial and natural photoperiods
Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2000; 279(6): R2270 - R2276.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
S. Usui, Y. Takahashi, and T. Okazaki
Range of entrainment of rat circadian rhythms to sinusoidal light-intensity cycles
Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2000; 278(5): R1148 - R1156.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
I-H. Tang, D. M. Murakami, and C. A. Fuller
Effects of square-wave and simulated natural light-dark cycles on hamster circadian rhythms
Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1999; 276(4): R1195 - R1202.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online