Seasonal changes in the short-term activity and ultradian rhythms of a cyprinid fish, the lake chub, Couesius plumbeus

1981 ◽  
Vol 59 (3) ◽  
pp. 486-492 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Seasonal Changes ◽  
Temporal Pattern ◽  
Circadian System ◽  
Cyprinid Fish ◽  
Constant Darkness ◽  
Ultradian Rhythms ◽  
Short Term ◽  
Free Running ◽  
Annual Changes ◽  
Couesius Plumbeus

The temporal pattern of the locomotor activity of a cyprinid fish, the lake chub, Couesius plumbeus, was examined under seasonally appropriate light–dark cycles that included twilights and under constant darkness. Photoperiodically entrained and free-running circadian activity from constant darkness was composed of nonrandomly distributed short-term activity components (0.5–3.5 h) with significant ultradian frequencies. In both cases there was an annual rhythm in the length of the ultradian periods, ranging from 0.7 h in winter to 2.5 h in summer. This pattern was accompanied by annual changes in the frequency distribution of short-term activity components. Ultradian periods were correlated with both daylength in the entraining light–dark cycles and the seasonal changes in the circadian period of fish free-running under constant darkness. These results suggest that the expression of ultradian rhythms and short-term locomotor bouts is controlled by a multioscillator circadian system.

Seasonal changes in the circadian period of the lake chub, Couesius plumbeus

1978 ◽  
Vol 56 (12) ◽  
pp. 2591-2596 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Seasonal Changes ◽  
Constant Darkness ◽  
Circadian Period ◽  
Minimum Period ◽  
Annual Variations ◽  
Circadian Organization ◽  
Annual Changes ◽  
The Times ◽  
Couesius Plumbeus

Systematic seasonal and annual changes are present in the length of the circadian period, τ, of the lake chub, Couesius plumbeus. Maximum and minimum period values of 28.1 and 24.8 h were recorded under constant darkness from fish obtained at the times of the winter and summer solstices, respectively. There was an asymmetric annual pattern in the τ values obtained from the increasing and decreasing photoperiods of spring and fall. Annual variations in τ were relatively independent of temperature. They were interpreted as being aftereffects of natural photoperiodic entrainment. Relations of annual changes in the length of the period to models of circadian organization and entrainment are examined.

Gonadal hormones organize and modulate the circadian system of the rat

1981 ◽  
Vol 241 (1) ◽  
pp. R62-R66 ◽  
Author(s):  
H. E. Albers
Keyword(s):  
Testosterone Propionate ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Gonadal Hormones ◽  
Circadian System ◽  
Female Rats ◽  
Constant Darkness ◽  
Before And After ◽  
Free Running ◽  
Free Running Period

The circadian wheel-running rhythms of gonadectomized adult male, female, and perinatally androgenized female rats, maintained in constant darkness, were examined before and after implantation of Silastic capsules containing cholesterol (C) or estradiol-17 beta (E). The free-running period of the activity rhythm (tau) before capsule implantation tended to be shorter in animals exposed to perinatal androgen. Administration of C did not reliably alter tau in any group. E significantly shortened tau in 100% of females injected with oil on day 3 of life. In females, injected with 3.5 micrograms testosterone propionate on day 3, and males, E shortened or lengthened tau, with the direction and magnitude of this change in tau inversely related to the length of the individual's pretreatment tau. These data indicate that the presence of perinatal androgen does not eliminate the sensitivity of the circadian system of the rat to estrogen, since estrogen alters tau in a manner that depends on its pretreatment length.

Dark pulses affect the circadian rhythm of activity in hamsters kept in constant light

1982 ◽  
Vol 242 (1) ◽  
pp. R44-R50 ◽  
Author(s):  
G. B. Ellis ◽  
R. E. McKlveen ◽  
F. W. Turek
Keyword(s):  
Response Curve ◽  
Phase Response Curve ◽  
Circadian System ◽  
Constant Light ◽  
Constant Darkness ◽  
Light Pulses ◽  
Subjective Night ◽  
Free Running ◽  
Male Golden Hamsters ◽  
Formal Properties

We compared the effects of light pulses in constant darkness (DD) and dark pulses in constant light (LL) on the free-running rhythm of locomotor activity in male golden hamsters. Light pulses yielded advances, delays, or no change in the rhythm of activity. These data conform to a typical phase-response curve; this curve was unaffected by pinealectomy. Dark pulses occurring either late in the subjective night or early in the subjective day had little effect. In contrast, dark pulses occurring either late in the subjective day or early in the subjective night altered the rhythm in one of three ways: advance of the rhythm; splitting into two components; or induction of a new component, in phase with the pulse. Because dark pulses in LL perturb the circadian system in a different manner than do light pulses in DD, they may have value in identifying heretofore unknown aspects of circadian systems. As such, the use of dark pulses to perturb circadian rhythmicity will be a useful tool in examining the formal properties of circadian systems.

Twilight and day length affects the seasonality of entrainment and endogenous circadian rhythms in a fish, Couesius plumbeus

1981 ◽  
Vol 59 (7) ◽  
pp. 1326-1334 ◽  
Author(s):  
Martin Kavaliers ◽  
Donald M. Ross
Keyword(s):  
Circadian Rhythms ◽  
Seasonal Changes ◽  
Phase Relationship ◽  
Day Length ◽  
Constant Darkness ◽  
Diurnal Activity ◽  
Circadian Period ◽  
Dark Cycle ◽  
Environmental Light ◽  
Couesius Plumbeus

Twilight and day-length portions of the light-dark cycle determine the seasonal course of (i) the phase relationship (ψ) between activity and the daily environmental light–dark cycle, (ii) the duration of activity (α), and (iii) the circadian period (τ) under constant darkness of the lake chub (Couesius plumbeus). With fish held under seasonally appropriate light–dark cycles with twilight (LD + t), the onset of diurnal activity occurred during dawn and its timing (ψonset) followed a bimodal annual pattern that was correlated with seasonal changes in the duration and physical characteristics of twilight. The end of activity occurred during dusk (ψoffset) and followed a unimodal annual pattern that was determined by day length. α followed a sigmoidal annual pattern under LD + t. The circadian period underwent significant seasonal changes with maximum and minimum τ values occurring during summer and winter, respectively. Fish that were entrained to rectangular light–dark cycles that excluded twilights (LD) failed to show any seasonal changes in ψ and τ and the sigmoidal relation between α and day length was absent.

Photic Regulation of Circadian Rhythms and Voluntary Ethanol Intake: Role of Melanopsin-expressing Intrinsically Photosensitive Retinal Ganglion Cells

2020 ◽  
pp. 074873042098122
Author(s):  
Matthew C. Hartmann ◽  
Walter D. McCulley ◽  
Samuel T. Johnson ◽  
Corey S. Salisbury ◽  
Nikhil Vaidya ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Circadian System ◽  
Genetically Engineered ◽  
Ethanol Intake ◽  
Constant Darkness ◽  
Retinal Ganglion ◽  
Retinal Photoreceptors ◽  
Genetically Engineered Mouse Model ◽  
Lighting Regimen

“Non-image-forming” (NIF) effects of light are mediated primarily by a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment, melanopsin (OPN4). These NIF functions include circadian entrainment, pupillary reflexes, and photic effects on sleep, mood, and cognition. We recently reported that mice of multiple genotypes exhibit reduced voluntary ethanol intake under both constant darkness (DD) and constant light (LL) relative to standard light-dark (LD) conditions. In the present study, we sought to determine whether these effects are mediated by melanopsin-expressing ipRGCs and their potential relationship to photic effects on the circadian system. To this end, we examined the effects of environmental lighting regimen on both ethanol intake and circadian activity rhythms in a genetically engineered mouse model ( Opn4aDTA/aDTA) in which melanopsin expression is completely blocked while ipRGCs are progressively ablated due to activation of attenuated diphtheria toxin A (aDTA) transgene under the control of the Opn4 promoter. As expected from previous studies, Opn4aDTA/aDTA mice displayed dramatic attenuation of circadian photosensitivity, but surprisingly, showed identical suppression of ethanol intake under both DD and LL as that seen in controls. These results demonstrate that the effects of lighting regimen on voluntary ethanol intake are independent of melanopsin-expressing ipRGCs and ipRGC-mediated photic effects on the circadian system. Rather, these effects are likely mediated by classical retinal photoreceptors and central pathways.

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.

Organization of rat circadian rhythms during daily infusion of melatonin or S20098, a melatonin agonist

1999 ◽  
Vol 277 (3) ◽  
pp. R812-R828 ◽  
Author(s):  
B. Pitrosky ◽  
R. Kirsch ◽  
A. Malan ◽  
E. Mocaer ◽  
P. Pevet
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Phase Response Curve ◽  
Constant Darkness ◽  
Time Interval ◽  
General Activity ◽  
Activity Peak ◽  
Free Running ◽  
Wheel Activity ◽  
Free Running Period

Daily administration of melatonin or S20098, a melatonin agonist, is known to entrain the free-running circadian rhythms of rats. The effects of the duration of administration on entrainment were studied. The animals demonstrated free-running circadian rhythms (running-wheel activity, body temperature, general activity) in constant darkness. Daily infusions of melatonin or S20098 for 1, 8, or 16 h entrained the circadian rhythms to 24 h. Two daily infusions of 1 h (separated by 8 h) entrained the activity peak within the shorter time interval. The entraining properties of melatonin and S20098 were similar and were affected neither by pinealectomy nor by infusion of 1- or 8-h duration. However, with 16-h infusion, less than half of the animals became entrained. Once entrained, the phase angle between the onset of infusion and the rhythms (onset of activity or acrophase of body temperature) increased with the duration of infusion. Before entrainment, the free-running period increased with the duration of infusion, an effect that was not predictable from the phase response curve.

Circadian and estrous cycle-dependent variations in blood pressure and heart rate in female rats

1994 ◽  
Vol 267 (5) ◽  
pp. R1250-R1256 ◽  
Author(s):  
H. Takezawa ◽  
H. Hayashi ◽  
H. Sano ◽  
H. Saito ◽  
S. Ebihara
Keyword(s):  
Heart Rate ◽  
Estrous Cycle ◽  
Female Rats ◽  
Constant Darkness ◽  
Dark Phase ◽  
Daily Rhythms ◽  
Abrupt Decrease ◽  
Internal Phase ◽  
Free Running ◽  
Cycle Dependent

To determine whether cardiovascular functions are controlled by the endogenous circadian system and whether they change with the estrous cycle in female rats, we measured mean arterial pressure (MAP), heart rate (HR), and spontaneous activity (ACT) of female rats using an implantable radiotelemetry device and a computerized data-collecting system. Under a 12:12-h light-dark (LD) cycle, these parameters exhibited daily rhythms that were entrained to the photic cycle. The patterns of the daily rhythms varied with estrous cycles, and variations were particularly marked in the proestrous stage. During the dark period of this stage, ACT levels were significantly higher, but HR was significantly lower than in other stages. Although the peak MAP occurred within 2 h after the onset of the dark phase in three of the estrous stages, it occurred around midnight in the proestrous stage. Such estrous cycle-dependent variations were eliminated by ovariectomy. The implantation of 17 beta-estradiol produced a gradual increase in MAP and an abrupt decrease in HR. During constant darkness, all three parameters were free running, maintaining the same internal phase relationships with each other as during LD cycles. These results indicate that daily variations in these parameters were controlled by the endogenous circadian oscillating system, that they vary with the estrous cycle in female rats, and that estrogen may be responsible for these estrous cycle-dependent variations.

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