Journal
FISH PHYSIOLOGY AND BIOCHEMISTRY
Volume 22, Issue 1, Pages 89-94Publisher
KLUWER ACADEMIC PUBL
DOI: 10.1023/A:1007861118404
Keywords
circadian rhythm; endogenous clock; light synchronization; photoperiod; sparid fish; teleost; zeitgeber
Categories
Ask authors/readers for more resources
Despite the abundant literature on circadian heart rate rhythms in fish, few studies have attempted to elucidate if such pattern is endogenous or if it is modulated by environmental cues. In this study, heart rates were continuously recorded in Sparus aurata acclimated to different light regimes (normal or shifted LD 12:12 cycle and a pulsed 0.75:0.75 LD cycle) to investigate the endogenous nature and the role of light on the circadian pattern of heart rate. Under LD 12:12, the daily pattern of heart rate showed higher values at night and lower rates during the day (average amplitude of the heart rate change of 10.6 +/- 5.7 beats min(-1)). The circadian pattern was maintained in animals under constant light but the amplitude was decreased (2.4 +/- 1.1 beats min(-1)). Light masks the expression of the rhythm because under a pulsed LD cycle, heart rate tracks the pulsed LD phases, increasing during the dark phase and decreasing during the light phase. Besides the ultradian pattern imposed, an underlying circadian rhythm was detected, which indicates that the rhythm is endogenous. However, the strong link between heart rate and light obtained under pulsed LD cycles suggest the timing mechanism to be mostly based on external light reception.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available