Effects of long-term restricted feeding on motor activity rhythm in the rat

1993 ◽  
Vol 265 (2) ◽  
pp. R467-R473 ◽  
Author(s):  
T. Cambras ◽  
J. Vilaplana ◽  
A. Diez-Noguera
Keyword(s):  
Motor Activity ◽  
Activity Rhythm ◽  
Red Light ◽  
Bright Light ◽  
Masking Effect ◽  
Restricted Feeding ◽  
Food Component ◽  
Free Running ◽  
Access To Food

The motor activity circadian rhythm of the rat is driven by at least two different pacemakers, one entrained by light-dark cycles and the other by periodic food access. The interaction between these two pacemakers generates the overt rhythm in many variables in the rat. In this paper we study the effects of restricted feeding (RF) for > 300 days on the motor activity of two groups of eight rats each (4 males and 4 females) that were kept under different light patterns. The first group was kept under dim red light, and the second group was kept initially for 70 days under bright light and afterward under dim red light. Rats had access to food for only 2 h/day. Results show that strong alterations in the motor activity pattern, such as relative coordination, bouncing, and several cases of entrainment, are shown in the first group. When these animals return to ad libitum feeding conditions the presence of the food component is clear, in some cases for > 20 days. In contrast, the rats that were previously subjected to bright light did not entrain to RF. In this group, there was a masking effect when lights were on, but a free-running component appeared when lights were off. The endogenous period (tau) of this component was not modified during the course of the experiment. After RF these rats showed a longer tau than the former group.(ABSTRACT TRUNCATED AT 250 WORDS)

Dissociation of motor activity circadian rhythm in rats after exposure to LD cycles of 4-h period

1997 ◽  
Vol 272 (1) ◽  
pp. R95-R102 ◽  
Author(s):  
J. Vilaplana ◽  
T. Cambras ◽  
A. Diez-Noguera
Keyword(s):  
Motor Activity ◽  
Activity Rhythm ◽  
Bright Light ◽  
Constant Light ◽  
Constant Darkness ◽  
Circadian Oscillators ◽  
Entrainment Process ◽  
Free Running ◽  
Anticipatory Activity ◽  
Degree Of Coupling

For > 30 days Wistar rats were subjected to six dark pulses per day (T4 cycles; 3 h light, 1 h dark) to study the possibility of dissociating their motor activity rhythm into distinct circadian components. Rats of both sexes were used, one-half of which were pinealectomized to examine the effect of the pineal gland on the entrainment process. Results show that when rats were maintained under T4 a 4-h rhythm in their motor activity was present. Rats showed anticipatory activity to dark phases, suggesting that the motor activity components are actually entrained to the external light/dark (LD) cycles. When rats were left under constant darkness after T4, some motor activity components coming from the dark phases free ran for several days with different circadian periods. This suggests that the motor activity pattern is generated by several circadian oscillators. Moreover, the free-running components of motor activity after T4 were more evident when T4 was applied after exposure to constant light than after exposure to constant darkness. These results support the hypothesis that the circadian system of the rat is formed by several circadian oscillators, whose degree of coupling depends on light conditions. In constant light, bright light may inhibit internal coupling within the system, making it subsequently more susceptible to the T4 cycles. No differences were observed between pinealectomized and sham-operated animals, although females were more sensitive to T4 cycles than males.

scholarly journals Bright light during lactation alters the functioning of the circadian system of adult rats

2000 ◽  
Vol 278 (1) ◽  
pp. R201-R208 ◽  
Author(s):  
M. M. Canal-Corretger ◽  
T. Cambras ◽  
J. Vilaplana ◽  
A. Díez-Noguera
Keyword(s):  
Motor Activity ◽  
Activity Rhythm ◽  
Bright Light ◽  
Circadian System ◽  
Constant Darkness ◽  
Adult Rats ◽  
Light Pulses ◽  
Circadian Time ◽  
Role Of Light

To examine the role of light in the maturation of the circadian pacemaker, twelve groups of rats were raised in different conditions of exposure to constant bright light (LL) during lactation: both duration and timing of LL were varied. We studied the motor activity rhythm of the rats after weaning, first under LL and then under constant darkness (DD). In DD, two light pulses [at circadian time 15 (CT15) and CT22] were applied to test the response of the pacemaker. Greater exposure to LL days during lactation increased the number of rhythmic animals and the amplitude of their motor activity rhythm in the LL stage and decreased the phase delay due to the light pulse at CT15. The timing of LL during lactation affected these variables too. Because the response of the adult to light depended on both the number and timing of LL days during lactation, the exposure to light at early stages may influence the development of the circadian system by modifying it structurally or functionally.

scholarly journals Physiological and Genetic Dissection of Sucrose Inputs to the Arabidopsis thaliana Circadian System

Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 334 ◽  
Author(s):  
Koumis Philippou ◽  
James Ronald ◽  
Alfredo Sánchez-Villarreal ◽  
Amanda M. Davis ◽  
Seth J. Davis
Keyword(s):  
Physiological Responses ◽  
Red Light ◽  
Genetic Dissection ◽  
Circadian Period ◽  
Free Running ◽  
Short And Long Term ◽  
Environment Perception ◽  
External Signals ◽  
Term Response

Circadian rhythms allow an organism to synchronize internal physiological responses to the external environment. Perception of external signals such as light and temperature are critical in the entrainment of the oscillator. However, sugar can also act as an entraining signal. In this work, we have confirmed that sucrose accelerates the circadian period, but this observed effect is dependent on the reporter gene used. This observed response was dependent on sucrose being available during free-running conditions. If sucrose was applied during entrainment, the circadian period was only temporally accelerated, if any effect was observed at all. We also found that sucrose acts to stabilize the robustness of the circadian period under red light or blue light, in addition to its previously described role in stabilizing the robustness of rhythms in the dark. Finally, we also found that CCA1 is required for both a short- and long-term response of the circadian oscillator to sucrose, while LHY acts to attenuate the effects of sucrose on circadian period. Together, this work highlights new pathways for how sucrose could be signaling to the oscillator and reveals further functional separation of CCA1 and LHY.

Effects of temperature on the circadian rhythm of pig-tailed macaques Macaca nemestrina

1983 ◽  
Vol 245 (6) ◽  
pp. R800-R804 ◽  
Author(s):  
H. Tokura ◽  
J. Aschoff
Keyword(s):  
Ambient Temperature ◽  
Activity Rhythm ◽  
Mammalian Species ◽  
Bright Light ◽  
Macaca Nemestrina ◽  
Temperature Cycle ◽  
Systematic Effect ◽  
Free Running ◽  
Dim Light ◽  
Effects Of Temperature

Activity rhythms of pig-tailed macaques, Macaca nemestrina, were recorded under three different conditions: 1) constant illumination (LL) and constant ambient temperature; 2) light-dark (LD) cycles with 12 h of bright light and 12 h of dim light (LD 12:12) at constant ambient temperature; 3) cycles with 12 h of high (32 degrees C) and 12 h of low temperature (17 degrees C) in LL. In constant conditions the period of the free-running rhythm was positively correlated with light intensity. Ambient temperature had no systematic effect on the period in LL of 0.45 and 45 lx; when measured in 100 or 450 lx, the period was consistently longer at 32 than at 17 degrees C. Temperature cycles with a range of 15 degrees C resulted in entrainment in three adult animals, but not at all tests; two adults and a couple of young animals were never entrained. Entrainment by temperature was less accurate than that by LD. The results demonstrate that a temperature cycle can entrain the circadian activity rhythm of an homeothermic mammalian species but that it is a very weak zeitgeber compared with LD cycle.

Daily injections of triazolam induce long-term changes in hamster circadian period

1990 ◽  
Vol 259 (3) ◽  
pp. R514-R520 ◽  
Author(s):  
O. Van Reeth ◽  
F. W. Turek
Keyword(s):  
Circadian Clock ◽  
Activity Rhythm ◽  
Phase Relationship ◽  
Term Treatment ◽  
Dark Cycle ◽  
Running Activity ◽  
Long Term Treatment ◽  
Free Running ◽  
Induced Changes

Previous experiments in hamsters indicate that daily injections of the short-acting benzodiazepine, triazolam, can entrain the free-running circadian activity rhythm to the period of the injections and that, after discontinuation of triazolam injections, the period of the free-running activity rhythm remains close to that of the previous injection schedule for 20-50 cycles. In this paper, we extend these findings and demonstrate that 1) long-term treatment with triazolam can induce aftereffects on the period of the circadian clock underlying the activity rhythm that can last for up to 100 days, 2) triazolam-induced changes in period can lead to a loss of effect of daily injections of triazolam which can be restored if the time of injection is altered, and 3) chronic treatment with triazolam also alters the period of the circadian clock in animals entrained to a light-dark cycle, and such changes in period alter the phase relationship between the circadian clock and the entraining light-dark cycle.

scholarly journals Coupling effect of locomotor activity on the rat’s circadian system

1998 ◽  
Vol 275 (2) ◽  
pp. R580-R587 ◽  
Author(s):  
Pedro Lax ◽  
Salvador Zamora ◽  
Juan A. Madrid
Keyword(s):  
Locomotor Activity ◽  
Wheel Running ◽  
Coupling Effect ◽  
Red Light ◽  
Bright Light ◽  
Circadian System ◽  
Circadian Rhythmicity ◽  
Lighting Conditions ◽  
Free Running ◽  
Free Running Period

Exercise is recognized to affect circadian rhythmicity in a variety of ways. It masks the expression of other behavioral and physiological rhythms, entrains the master pacemaker, and influences the free-running period of other rhythms. In this paper we study the influence of exercise on the organization of the timing system by analyzing the effect of voluntary locomotor activity on the circadian feeding behavior of rats subjected to different lighting conditions. The availability of wheel running prevented loss of feeding circadian rhythmicity under constant bright light (LL) but did not elicit any circadian pattern in rats showing a previous arrhythmic pattern. Under dim red light (DR), the rhythm was more pronounced in exercising than in sedentary rats, while wheel-running availability accelerated the emergence of circadian rhythmicity in arrhythmic animals that were moved from LL to DR. These results can be explained by the existence of a positive feedback loop between physical exercise and its pacemaker and also suggest that exercise changes the functioning of the circadian system to facilitate the emergence of circadian rhythms in previously arrhythmic animals.

Manifestation of circadian rhythm under constant light depends on lighting conditions during lactation

1997 ◽  
Vol 272 (4) ◽  
pp. R1039-R1046 ◽  
Author(s):  
T. Cambras ◽  
M. M. Canal ◽  
A. Torres ◽  
J. Vilaplana ◽  
A. Diez-Noguera
Keyword(s):  
Circadian Rhythm ◽  
Motor Activity ◽  
Activity Rhythm ◽  
Bright Light ◽  
Constant Light ◽  
Continuous Illumination ◽  
Continuous Darkness ◽  
Adult Rats ◽  
Lighting Conditions ◽  
Variance Explained

Adult rats transferred to continuous illumination (LL) show a disruption of circadian rhythms, although the mechanisms underlying this effect are not yet well known. In previous experiments, we found that when rats were born and raised under LL they showed an ultradian pattern during the first 10 days after weaning, but afterward they generated a circadian rhythm that was maintained until adulthood. It was not clear whether this evolution was attributable to the influence of the rhythm of the mother or to the effect of constant light. Here, we have studied the motor activity rhythm of young rats maintained under LL after weaning, taking into account the conditions to which they were exposed during lactation [LL or continuous darkness (DD)]. To check the possible effect of the rhythm of the dam, on the day of delivery some of the dams were blinded, others were subjected to a restricted feeding schedule of 3 h/day, and the others were used as controls. For each rat, the period of the circadian rhythm and the percentage of variance explained by this rhythm were calculated. Results show that all rats maintained under LL during lactation expressed a circadian rhythm in their motor activity. However, rats maintained under DD during lactation did not. This effect did not seem to be dependent on the type of dam. These results suggest that the rhythm of the dams does not affect the manifestation of the rhythm of the pups and that the expression of circadian rhythmicity under constant bright light depends on the lighting conditions under which the animals were maintained during lactation, which could affect the development of the circadian pacemaker or the retina.

scholarly journals An Efficient Alternative to the CDC Gravid Trap for Southern House Mosquito (Diptera: Culicidae) Surveillance

2020 ◽  
Author(s):  
Timothy D McNamara ◽  
Thomas A O’Shea-Wheller ◽  
Nicholas DeLisi ◽  
Emily Dugas ◽  
Kevin A Caillouet ◽  
...  
Keyword(s):  
United States ◽  
Mosquito Species ◽  
Red Light ◽  
Light Trap ◽  
The United States ◽  
Light Traps ◽  
Efficient Alternative ◽  
Gravid Trap ◽  
Trapping Trials

Abstract West Nile virus (WNV) is the most prevalent arbovirus found throughout the United States. Surveillance of surface breeding Culex vectors involved in WNV transmission is primarily conducted using CDC Gravid traps. However, anecdotal claims from mosquito abatement districts in Louisiana assert that other trap types may be more suited to WNV surveillance. To test the validity of these assertions, we conducted a series of trapping trials and WNV surveillance over 3 yr to compare the efficacy of multiple trap types. First, we compared the CDC Gravid trap, CO2-baited New Standard Miniature Blacklight traps, and CO2-baited CDC light traps with either an incandescent light, a red light, or no light. We found that the CDC Gravid trap and CO2-baited no-light CDC Light trap collected the most mosquitoes. Second, we conducted additional, long-term trapping and WNV surveillance to compare these two trap types. We found that CO2-baited no-light CDC traps collected more of the local WNV vector, Culex quinquefasciatus (Say, Diptera, Culicidae), and detected WNV with greater sensitivity. Finally, we conducted trapping to compare the physiological states of Cx. quinquefasciatus and diversity of collected mosquitoes. CO2-baited no-light CDC light traps collected more unfed Cx. quinquefasciatus while Gravid traps collected more blooded Cx. quinquefasciatus; both traps collected the same number of gravid Cx. quinquefasciatus. Additionally, we found that CO2-baited no-light CDC light traps collected a larger diversity of mosquito species than Gravid traps.

scholarly journals Effects of Time-Restricted Feeding on Supramaximal Exercise Performance and Body Composition: A Randomized and Counterbalanced Crossover Study in Healthy Men

2021 ◽  
Vol 18 (14) ◽  
pp. 7227
Author(s):  
Joana M. Correia ◽  
Inês Santos ◽  
Pedro Pezarat-Correia ◽  
Cláudia Minderico ◽  
Brad J. Schoenfeld ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Mass ◽  
Exercise Performance ◽  
Fat Free Mass ◽  
Restricted Feeding ◽  
Supramaximal Exercise ◽  
Mean Power ◽  
Post Intervention ◽  
Dietary Record

Using a crossover design, we explored the effects of both short- and long-term time-restricted feeding (TRF) vs. regular diet on Wingate (WnT) performance and body composition in well-trained young men. Twelve healthy male physical education students were included (age: 22.4 ± 2.8 years, height: 174.0 ± 7.1 cm, body mass: 73.6 ± 9.5 kg, body mass index: 24.2 ± 2.0 kg/m2). The order of dieting was randomized and counterbalanced, and all participants served as their own controls. TRF was limited to an 8-h eating window and non-TRF involved a customary meal pattern. Participants performed WnT tests and body composition scans at baseline, post-one and post-four weeks of the assigned diet. Before testing, participants were asked to fill out a dietary record over four consecutive days and were instructed to continue their habitual training throughout the study. Energy intake and macronutrient distribution were similar at baseline in both conditions. WnT mean power and total work output increased post-four weeks of TRF. Both conditions were similarly effective in increasing fat-free mass after four weeks of intervention. However, there was no correlation between change in fat-free mass and WnT mean power after TRF. TRF did not elicit any changes in WnT performance or body composition one week post-intervention. Thus, long-term TRF can be used in combination with regular training to improve supramaximal exercise performance in well-trained men.

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