A Comparative-Study of Circadian Activity Patterns of 2 New Guinean Dasyurid Marsupials, Phascolosorex-Dorsalis and Antechinus-Habbema

1991 ◽  
Vol 39 (6) ◽  
pp. 661 ◽  
Author(s):  
PA Woolley ◽  
SA Raftopoulos ◽  
GJ Coleman ◽  
SM Armstrong
Keyword(s):  
Ecological Niche ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Activity Patterns ◽  
Food Presentation ◽  
Circadian Pacemaker ◽  
Diurnal Activity ◽  
Circadian Activity ◽  
Dark Cycle ◽  
Feeding Regimen

Five aspects of the circadian activity rhythm (wheel running, feeding, drinking, duration of time in, and visits to, the nest box) were studied for 129 days in two species of New Guinean dasyurid marsupials that co-exist in mid-montane semi-mossforest. When housed under controlled laboratory conditions, Phascolosorex dorsalis exhibited a diurnal activity pattern whereas Antechinus habbema was nocturnal. Manipulation of the feeding regimen and reversal of the 12: 12 light-dark cycle demonstrated that the diurnal activity of P. dorsalis was not due to synchronisation to food presentation but reflected the behavioural output from an endogenous circadian pacemaker. P. dorsalis appears to be unique among dasyurids in its diurnality. Results are interpreted in terms of the ecological niche being a division of time as well as space.

Disrupted circadian rhythms in VIP- and PHI-deficient mice

2003 ◽  
Vol 285 (5) ◽  
pp. R939-R949 ◽  
Author(s):  
Christopher S. Colwell ◽  
Stephan Michel ◽  
Jason Itri ◽  
Williams Rodriguez ◽  
J. Tam ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Activity Patterns ◽  
Circadian System ◽  
Diurnal Rhythms ◽  
Constant Darkness ◽  
Light Cycle ◽  
Wild Type ◽  
Deficient Mice

The related neuropeptides vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) are expressed at high levels in the neurons of the suprachiasmatic nucleus (SCN), but their function in the regulation of circadian rhythms is unknown. To study the role of these peptides on the circadian system in vivo, a new mouse model was developed in which both VIP and PHI genes were disrupted by homologous recombination. In a light-dark cycle, these mice exhibited diurnal rhythms in activity which were largely indistinguishable from wild-type controls. In constant darkness, the VIP/PHI-deficient mice exhibited pronounced abnormalities in their circadian system. The activity patterns started ∼8 h earlier than predicted by the previous light cycle. In addition, lack of VIP/PHI led to a shortened free-running period and a loss of the coherence and precision of the circadian locomotor activity rhythm. In about one-quarter of VIP/PHI mice examined, the wheel-running rhythm became arrhythmic after several weeks in constant darkness. Another striking example of these deficits is seen in the split-activity patterns expressed by the mutant mice when they were exposed to a skeleton photoperiod. In addition, the VIP/PHI-deficient mice exhibited deficits in the response of their circadian system to light. Electrophysiological analysis indicates that VIP enhances inhibitory synaptic transmission within the SCN of wild-type and VIP/PHI-deficient mice. Together, the observations suggest that VIP/PHI peptides are critically involved in both the generation of circadian oscillations as well as the normal synchronization of these rhythms to light.

Activity rhythm of golden hamster (Mesocricetus auratus) can be entrained to a 19-h light-dark cycle

2005 ◽  
Vol 289 (4) ◽  
pp. R998-R1005 ◽  
Author(s):  
Juan J. Chiesa ◽  
Montserrat Anglès-Pujolràs ◽  
Antoni Díez-Noguera ◽  
Trinitat Cambras
Keyword(s):  
Golden Hamster ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Mesocricetus Auratus ◽  
Precise Determination ◽  
Dark Cycle ◽  
Running Wheel ◽  
Running Activity ◽  
Wheel Running Activity

Both temporary access to a running wheel and temporary exposure to light systematically influence the phase producing entrainment of the circadian activity rhythm in the golden hamster ( Mesocricetus auratus). However, precise determination of entrainment limits remains methodologically difficult, because such calculations may be influenced by varying experimental paradigms. In this study, effects on the entrainment of the activity pattern during successive light-dark (LD) cycles of stepwise decreasing periods, as well as wheel running activity, were investigated. In particular, the hamster activity rhythm under LD cycles with a period (T) shorter than 22 h was studied, i.e., when the LD cycle itself had been shown to be an insufficiently strong zeitgeber to synchronize activity rhythms. Indeed, it was confirmed that animals without a wheel do not entrain under 11:11-h LD cycles (T = 22 h). Subsequently providing hamsters continuous access to a running wheel established entrainment to T = 22 h. Moreover, this paradigm underwent further reductions of the T period to T = 19.6 h without loss of entrainment. Furthermore, restricting access to the wheel did not result in loss of entrainment, while even entrainment to T = 19 h was observed. To explain this observed shift in the lower entrainment limit, our speculation centers on changes in pacemaker response facilitated by stepwise changes of T spaced very far apart, thus allowing time for adaptation.

scholarly journals RCAN1 Knockout and Overexpression Recapitulate an Ensemble of Rest-activity and Circadian Disruptions Characteristic of Down Syndrome, Alzheimer’s Disease, and Normative Aging

2021 ◽  
Author(s):  
Helen Wong ◽  
Jordan M. Buck ◽  
Curtis Borski ◽  
Jessica Pafford ◽  
Bailey N. Keller ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Down Syndrome ◽  
Wheel Running ◽  
Activity Patterns ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Free Running ◽  
Rest Activity ◽  
Young Mice

Abstract Background: Regulator of calcineurin 1 (RCAN1) is overexpressed in Down syndrome (DS), but RCAN1 levels are also increased in Alzheimer's disease (AD) and normal aging. AD is highly comorbid among individuals with DS and is characterized in part by progressive neurodegeneration that resembles accelerated aging. Importantly, abnormal RCAN1 levels have been demonstrated to promote memory deficits and pathophysiology symptomatic of DS, AD, and aging. Anomalous diurnal rest-activity patterns and circadian rhythm disruptions are also common in DS, AD, and aging and have been implicated in facilitating age-related cognitive decline and AD progression. However, no prior studies have assessed whether RCAN1 dysregulation may also promote the age-associated alteration of rest-activity profiles and circadian rhythms, which could in turn contribute to neurodegeneration in DS, AD, and aging. Methods: The present study examined the impacts of RCAN1 deficiency and overexpression on the photic entrainment, circadian periodicity, intensity and distribution, diurnal patterning, and circadian rhythmicity of wheel running in young (3-6 months old) and aged (9-14 months old) mice. All data were initially analyzed by multifactorial ANOVA with variables of genotype, age, treatment, and sex considered as dependent variables.Results: We found that daily RCAN1 levels in the hippocampi of light-entrained young mice are generally constant and that balanced RCAN1 expression is necessary for normal circadian locomotor activity rhythms. While the light-entrained diurnal period was unaltered, RCAN1-null and -overexpressing mice displayed lengthened endogenous (free-running) circadian periods like mouse models of AD and aging. In light-entrained young mice, RCAN1 knockout and overexpression also recapitulated the general hypoactivity, diurnal rest-wake pattern fragmentation, and attenuated amplitudes of circadian activity rhythms reported in DS, preclinical and clinical AD, healthily aging individuals, and rodent models thereof. Under constant darkness, RCAN1-null and -overexpressing mice displayed altered locomotor behavior indicating circadian clock dysfunction. Using the Dp(16)1Yey/+ (Dp16) mouse model for DS, which expresses three copies of Rcan1, we found reduced wheel running activity and rhythmicity in both light-entrained and free-running young Dp16 mice like young RCAN1-overexpressing mice. Critically, these diurnal and circadian deficits were rescued in part or entirely by restoring Rcan1 to two copies in Dp16 mice. Conclusions: Collectively, this study's findings suggest that both loss and aberrant gain of RCAN1 precipitate anomalous light-entrained diurnal and circadian activity patterns emblematic of DS, AD, and aging.

scholarly journals Optimization of circadian responses with shorter and shorter millisecond flashes

2019 ◽  
Vol 15 (8) ◽  
pp. 20190371 ◽  
Author(s):  
Sevag Kaladchibachi ◽  
David C. Negelspach ◽  
Jamie M. Zeitzer ◽  
Fabian Fernandez
Keyword(s):  
Response Curve ◽  
Energy Content ◽  
Light Exposure ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Phase Shifting ◽  
Maximal Response ◽  
Circadian Pacemaker ◽  
Circadian Activity ◽  
Left Shift

Recent work suggests that the circadian pacemaker responds optimally to millisecond flashes of light, not continuous light exposure as has been historically believed. It is unclear whether these responses are influenced by the physical characteristics of the pulsing. In the present study, Drosophila ( n = 2199) were stimulated with 8, 16 or 120 ms flashes. For each duration, the energy content of the exposure was systematically varied by changing the pulse irradiance and the number of stimuli delivered over a fixed 15 min administration window (64 protocols surveyed in all). Results showed that per microjoule invested, 8 ms flashes were more effective at resetting the circadian activity rhythm than 16- and 120 ms flashes (i.e. left shift of the dose–response curve, as well as a higher estimated maximal response). These data suggest that the circadian pacemaker's photosensitivity declines within milliseconds of light contact. Further introduction of light beyond a floor of (at least) 8 ms leads to diminishing returns on phase-shifting.

scholarly journals Age-related changes in circadian responses to dark pulses

2000 ◽  
Vol 279 (2) ◽  
pp. R586-R590 ◽  
Author(s):  
Marilyn J. Duncan ◽  
Anthony W. Deveraux
Keyword(s):  
Wheel Running ◽  
Activity Rhythm ◽  
Circadian Pacemaker ◽  
Running Activity ◽  
Age Related ◽  
Wheel Running Activity ◽  
Significant Difference ◽  
Time Signals ◽  
Dark Pulse ◽  
Age Related Changes

Aging involves many alterations in circadian rhythms, including a loss of sensitivity to both photic and nonphotic time signals. This study investigated the sensitivity of young and old hamsters to the phase advancing effect of a 6-h dark pulse on the locomotor activity rhythm. Each hamster was tested four times during a period of ∼9 mo; periods of exposure to a 14-h photoperiod were alternated with the periods of exposure to constant light (20–80 lx), during which the dark pulses were administered. There was no significant difference in the phase shifts exhibited by the young (4–10 mo) and old hamsters (19–25 mo) or in the amount of wheel running activity displayed during each dark pulse. However, young hamsters had a significantly greater propensity to exhibit split rhythms immediately after the dark pulses. These results suggest that, although aging does not reduce the sensitivity of the circadian pacemaker to this nonphotic signal, it alters one property of the pacemaker, i.e., the flexibility of the coupling of its component oscillators.

Sex differentiation of t-e circadian system in the golden hamster

1980 ◽  
Vol 238 (1) ◽  
pp. R97-R101 ◽  
Author(s):  
I. Zucker ◽  
K. M. Fitzgerald ◽  
L. P. Morin
Keyword(s):  
Testosterone Propionate ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Sex Differentiation ◽  
Estradiol Benzoate ◽  
Circadian System ◽  
Normal Male ◽  
Circadian Activity ◽  
Neural Connections ◽  
Free Running

The effect of estradiol benzoate (EB) on free-running circadian activity rhythms was studied in gonadectomized hamsters maintained in constant dim illumination. EB shortened the period (tau) of the female, but not of the male circadian activity rhythm. Responsiveness of the circadian system to EB was subject to sexual differentiation. The circadian period of wheel running by female hamsters given a single injection of testosterone propionate on the day of birth did not shorten in response to EB in adulthood. This failure to respond to EB also was observed in normal male hamsters, and was different from the response shown by normal females. Preliminary data suggest that tau of the activity rhythm of males castrated on the day of birth is shortened during EB treatment in adulthood. The differential effects of estradiol on tau are related to anatomic differences between the sexes in neural connections of the substrate for circadian rhythms.

A low-protein diet ameliorates disrupted diurnal locomotor activity in rats after portacaval anastomosis

1996 ◽  
Vol 271 (4) ◽  
pp. G555-G560 ◽  
Author(s):  
P. E. Steindl ◽  
D. L. Coy ◽  
B. Finn ◽  
P. C. Zee ◽  
A. T. Blei
Keyword(s):  
Hepatic Encephalopathy ◽  
Locomotor Activity ◽  
Protein Content ◽  
Activity Rhythm ◽  
Activity Patterns ◽  
High Protein Diet ◽  
Protein Diet ◽  
Portacaval Anastomosis ◽  
Sham Operation ◽  
Dark Cycle

In previous studies we noted a disruption of the circadian locomotor activity rhythm in rats after portacaval anastomosis (PCA). To examine whether this abnormality is related to factors that aggravate hepatic encephalopathy in humans, we studied the effect of dietary formulation and protein content on body weight, locomotor activity, and entrainment to the light-dark cycle in rats after PCA or sham operation. Postoperative weight loss was prevented by pair-feeding with a purified liquid diet. However, the behavioral abnormalities persisted in PCA rats fed a high-protein diet, with a reduction in total activity and entrainment to the light-dark cycle. These were ameliorated by a low dietary protein content. Since this treatment reduces the load of gut-derived nitrogenous substances that might alter brain metabolism, our data strengthen the hypothesis that the abnormal circadian activity patterns in PCA rats may be part of the spectrum of hepatic encephalopathy.

Lability and diversity of circadian rhythms of cotton rats Sigmodon hispidus

1983 ◽  
Vol 244 (3) ◽  
pp. R338-R346 ◽  
Author(s):  
P. G. Johnston ◽  
I. Zucker
Keyword(s):  
Wheel Running ◽  
Activity Rhythm ◽  
Constant Darkness ◽  
Sigmodon Hispidus ◽  
Diurnal Activity ◽  
Adult Rats ◽  
Cotton Rats ◽  
Activity Types ◽  
Activity Cycles ◽  
Spontaneous Phase

Cotton rats (Sigmodon hispidus) were maintained from birth in constant LD 14:10 photoperiods and temperatures. Wheel running was diurnal for 6 of 13 juvenile rats and nocturnal for most others. Most diurnal rats eventually added nocturnal activity components. In constant darkness the activity rhythms of adult rats free-ran with a period of 23.2 +/- 0.3 h; in constant illumination the period was 24.7 +/- 0.1 h, in conformation to Aschoff's rule for nocturnal rodents. Some previously nocturnal adult rats eventually adopted stable diurnal activity cycles and other were successively nocturnal, diurnal for 6 mo, and then nocturnal again while maintained in the LD 14:10 photoperiod. The existence of multiple activity types, as well as the spontaneous inversions from nocturnal to diurnal status substantiate and extend field observations of this species. Seasonal inversions from nocturnal to diurnal activity, previously attributed to fluctuating environmental conditions, may also be subject to regulation by endogenous processes. It is suggested that spontaneous phase reversals in activity reflect changes in entrainment of circadian pacemakers by the light-dark cycle or altered relations between such pacemakers and the overt activity rhythm.

Sign in / Sign up

Export Citation Format

Share Document