Phase-response and Aschoff illuminance curves for locomotor activity rhythm of the rat

1984 ◽  
Vol 246 (3) ◽  
pp. R299-R304 ◽  
Author(s):  
T. L. Summer ◽  
J. S. Ferraro ◽  
C. E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Wheel Running ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Phase Response ◽  
Sprague Dawley ◽  
Continuous Darkness ◽  
Light Pulses ◽  
Log Steps

A phase-response curve (PRC) for the circadian rhythm of locomotor activity was constructed for female Sprague-Dawley-derived rats kept in continuous darkness (DD) except when given a 1-h light pulse (150 lx) once each 2 wk. By use of the circadian onset of wheel running as the phase-reference point, the free-running period (tau) in DD was 24.09 h. Maximum phase delays and phase advances occurred in response to light pulses given during the first 5 and last 6 h of activity, respectively. The delay-to-advance ratio (D/A) of the PRC was 1.5. In a separate group of rats exposed to continuous light, tau increased by 1.45 h as illuminance was increased in log steps from 0.1 to 10 lx, thus demonstrating the Aschoff effect in rats. This increase in tau was large, considering the relatively low D/A of the PRC, suggesting that factors in addition to the D/A contribute to the Aschoff effect.

Administering triazolam on a circadian basis entrains the activity rhythm of hamsters

1989 ◽  
Vol 256 (3) ◽  
pp. R639-R645
Author(s):  
O. Van Reeth ◽  
F. W. Turek
Keyword(s):  
Response Curve ◽  
Wheel Running ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Relationship ◽  
Phase Shifts ◽  
Phase Response ◽  
Light Pulses ◽  
Circadian Time ◽  
Free Running

A single injection of the short-acting benzodiazepine, triazolam, can induce permanent phase shifts in the circadian rhythm of locomotor activity in free-running hamsters, with the direction and magnitude of the phase shifts being dependent on the circadian time of treatment. The shape of the "phase-response curve" to triazolam injections is totally different from that for light pulses. These findings raise the possibility that repeated injections of triazolam on a circadian basis might be capable of entraining the circadian pacemaker underlying the activity rhythm of hamsters and that the entrainment pattern might differ from that observed in animals entrained to light pulses. To test this hypothesis, blind hamsters received intraperitoneal injections of triazolam (or vehicle) every 23.34, 23.72, 24.00 or 24.66 h for 19-20 days, and the effect of these injections on the period of the rhythm of wheel-running behavior was determined during and after treatment. Repeated injections of 0.1 mg triazolam at these time intervals resulted in the entrainment of the activity rhythm in 36 of 40 animals, whereas 0 of 40 animals entrained to vehicle injections. Importantly, the phase relationship between triazolam injections and the circadian activity rhythm was dependent on the period of drug treatment and could be predicted from the phase-response curve to single injections of triazolam. These phase relationships are dramatically different from those observed between the activity rhythm and 1-h light pulses presented at similar circadian intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Notizen: Weak and Strong Phase Shifting in the Activity Rhythm of Leucophaea maderae (Blaberidae)after Light Pulses of High Intensity

1977 ◽  
Vol 32 (5-6) ◽  
pp. 464-465 ◽  
Author(s):  
Gottfried Wiedenmann
Keyword(s):  
High Intensity ◽  
Response Curve ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Response ◽  
Strong Phase ◽  
Light Pulses ◽  
Leucophaea Maderae ◽  
Running Activity ◽  
High Intensity Light

Abstract In the running activity of the cockroach Leucophaea maderae a strong phase response curve is found when using high intensity light pulses (80 000 lx and about 12 hours duration). The phase response curve has an unsymmetric shape: delays are larger than advances. The phase jump lies about 2 hours after subjective midnight.

CIRCADIAN LOCOMOTOR ACTIVITY AND ITS ENTRAINMENT BY FOOD IN THE CRAYFISH PROCAMBARUS CLARKI

1994 ◽  
Vol 190 (1) ◽  
pp. 9-21 ◽  
Author(s):  
F F De Miguel ◽  
H Aréchiga
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
Food Reinforcement ◽  
Continuous Light ◽  
Food Delivery ◽  
Continuous Darkness ◽  
Locomotor Activity Rhythm ◽  
Activity Peak ◽  
Free Running ◽  
Two Peaks

The aim of our experiments has been to study the effect of light and food in the locomotor activity rhythm of the crayfish Procambarus clarki. Experiments were carried out under light:dark (LD) cycles of 12 h:12 h, under continuous darkness (DD) and under continuous light (LL). Under LD cycles, two peaks of activity were observed during the night phase of the cycle, while resting was characteristic of the day phase. Under DD or LL, it was possible to follow a free-running rhythm with a periodicity of 22.3±0.84 h in DD and 24.8±0.27 h in LL, typical of circadian rhythms of nocturnal species. A single delivery of food in the day phase of the LD cycle resulted in an outburst of locomotor activity that lasted for several hours. In the ensuing days, an activity peak appeared in phase with the time of food delivery. The food-related activity peak could be followed for up to 2 weeks without food reinforcement. Under DD and LL, food induced an activity rhythm in previously arrhythmic animals. Here the period was longer than 24 h in DD (26.2±0.12 h) and shorter in LL (22.5±0.46 h). Together, these results strongly suggest that light and food may play a role entraining a locomotor activity rhythm in crayfish.

Photoperiod differentially modulates photic and nonphotic phase response curves of hamsters

2004 ◽  
Vol 286 (3) ◽  
pp. R539-R546 ◽  
Author(s):  
J. A. Evans ◽  
J. A. Elliott ◽  
M. R. Gorman
Keyword(s):  
Wheel Running ◽  
Phase Response Curve ◽  
Phase Shifts ◽  
Phase Response ◽  
Cycle Phase ◽  
Phase Resetting ◽  
Response Curves ◽  
Syrian Hamsters ◽  
Light Pulses ◽  
Circadian Time

Circadian pacemakers respond to light pulses with phase adjustments that allow for daily synchronization to 24-h light-dark cycles. In Syrian hamsters, Mesocricetus auratus, light-induced phase shifts are larger after entrainment to short daylengths (e.g., 10 h light:14 h dark) vs. long daylengths (e.g., 14 h light:10 h dark). The present study assessed whether photoperiodic modulation of phase resetting magnitude extends to nonphotic perturbations of the circadian rhythm and, if so, whether the relationship parallels that of photic responses. Male Syrian hamsters, entrained for 31 days to either short or long daylengths, were transferred to novel wheel running cages for 2 h at times spanning the entire circadian cycle. Phase shifts induced by this stimulus varied with the circadian time of exposure, but the amplitude of the resulting phase response curve was not markedly influenced by photoperiod. Previously reported photoperiodic effects on photic phase resetting were verified under the current paradigm using 15-min light pulses. Photoperiodic modulation of phase resetting magnitude is input specific and may reflect alterations in the transmission of photic stimuli.

Melatonin and activity rhythm responses to light pulses in mice with the Clock mutation

2003 ◽  
Vol 284 (5) ◽  
pp. R1231-R1240 ◽  
Author(s):  
David J. Kennaway ◽  
Athena Voultsios ◽  
Tamara J. Varcoe ◽  
Robert W. Moyer
Keyword(s):  
Wheel Running ◽  
Activity Rhythm ◽  
Mutant Mice ◽  
Constant Darkness ◽  
Wild Type ◽  
Continuous Darkness ◽  
Light Pulses ◽  
Essentially Normal ◽  
Running Activity ◽  
Wheel Running Activity

Melatonin and wheel-running rhythmicity and the effects of acute and chronic light pulses on these rhythms were studied in Clock Δ19 mutant mice selectively bred to synthesize melatonin. Homozygous melatonin-proficient Clock Δ19 mutant mice ( Clock Δ19/Δ19 -MEL) produced melatonin rhythmically, with peak production 2 h later than the wild-type controls (i.e., just before lights on). By contrast, the time of onset of wheel-running activity occurred within a 20-min period around lights off, irrespective of the genotype. Melatonin production in the mutants spontaneously decreased within 1 h of the expected time of lights on. On placement of the mice in continuous darkness, the melatonin rhythm persisted, and the peak occurred 2 h later in each cycle over the first two cycles, consistent with the endogenous period of the mutant. This contrasted with the onset of wheel-running activity, which did not shift for several days in constant darkness. A light pulse around the time of expected lights on followed by constant darkness reduced the expected 2-h delay of the melatonin peak of the mutants to ∼1 h and advanced the time of the melatonin peak in the wild-type mice. When the Clock Δ19/Δ19 -MEL mice were maintained in a skeleton photoperiod of daily 15-min light pulses, a higher proportion entrained to the schedule (57%) than melatonin-deficient mutants (9%). These results provide compelling evidence that mice with the Clock Δ19 mutation express essentially normal rhythmicity, albeit with an underlying endogenous period of 26–27 h, and they can be entrained by brief exposure to light. They also raise important questions about the role of Clock in rhythmicity and the usefulness of monitoring behavioral rhythms compared with hormonal rhythms.

Circadian pacemakers in lizards: phase-response curves and effects of pinealectomy

1983 ◽  
Vol 244 (6) ◽  
pp. R857-R864 ◽  
Author(s):  
H. Underwood
Keyword(s):  
Continuous Light ◽  
Phase Response ◽  
Fluorescent Light ◽  
Response Curves ◽  
Continuous Darkness ◽  
Phase Response Curves ◽  
Light Pulses ◽  
Running Activity ◽  
Free Running ◽  
Free Running Period

Phase-response curves (PRCs) for 6-h fluorescent light pulses are described for both intact (sham-pinealectomized) and pinealectomized iguanid lizards (Sceloporus occidentalis). Although strongly diurnal in habit the PRC for intact lizards is more typical of those seen in nocturnal rodents. Other "nocturnal" characteristics of this lizard include the fact that the average free-running period (tau) is less than 24 h and the average tau in continuous light is longer than that observed in continuous darkness. The PRC for pinealectomized lizards is greatly distorted relative to that obtained from intact lizards. This "distortion" is discussed in terms of the role of the pineal as a coupling device or as a pacemaker within a multioscillator circadian system. In some individuals pinealectomy was also associated with 1) increased instability in free-running activity rhythms or arrhythmicity and 2) nocturnal entrainment to LD 12:12.

The Daily Rhythm of Activity of the Cockroach, Blatta Orientalis L

1940 ◽  
Vol 17 (3) ◽  
pp. 267-277 ◽  
Author(s):  
D. L. GUNN
Keyword(s):  
Activity Rhythm ◽  
Continuous Light ◽  
Locomotory Activity ◽  
Continuous Darkness ◽  
Daily Cycle ◽  
Blatta Orientalis ◽  
Physical Stimuli ◽  
Inactive Phase ◽  
Set Up ◽  
Main Activity

1. In an aktograph at 25.5°C., at upwards of 75% relative humidity and with food present, the average locomotory activity of the cockroach per day does not depend on whether there is continuous light for weeks, or continuous darkness, or a daily alternation of light and darkness. 2. When temperature and humidity do not vary during the day and other factors are kept as constant as possible, the cockroach's activity can be largely concentrated into any desired half of the day, simply by suitably adjusting the time of onset of the half-day's darkness. A rhythm can thus be set up, so that the main activity occurs at the same hours each day. 3. This activity rhythm persists for some days in continuous light or continuous darkness, but eventually activity becomes much more evenly spread over the whole day, leaving only a slight residual rhythm which is unrelated to the previous conspicuous one. A new conspicuous rhythm can then be started at once by alternation of light and darkness. 4. There are indications that animal responses to physical stimuli may depend to a considerable extent on whether the animal is in the active or the inactive phase of its daily cycle. A method is suggested for making it possible to study the nocturnal phase during the daytime.

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