MAGNETIC FLUCTUATIONS AFFECT CIRCADIAN PATTERNS OF LOCOMOTOR ACTIVITY IN ZEBRAFISH (PRELIMINARY DATA)

2021 ◽  
pp. 15-25
Author(s):  
V. Krylov ◽  
E. Izvekov ◽  
V. Pavlova ◽  
N. Pankova ◽  
E. Osipova
Keyword(s):  
Magnetic Field ◽  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Danio Rerio ◽  
Preliminary Data ◽  
Magnetic Fluctuations ◽  
Constant Illumination ◽  
Free Running ◽  
Circadian Patterns

The locomotor activity of zebrafish (Danio rerio) has a pronounced, well-studied circadian rhythm. Under constant illumination, the period of free-running locomotor activity in this species usually becomes less than 24 hours. To evaluate the entraining capabilities of slow magnetic variations, zebrafish locomotor activity was evaluated at constant illumination and fluctuating magnetic field with a period of 26.8 hours. Lomb-Scargle periodogram revealed significant free-running rhythms of locomotor activity and related behavioral endpoints with a period close to 27 hours. Obtained results reveal the potential of slow magnetic fluctuations for entrainment of the circadian rhythms in zebrafish. The putative mechanisms responsible for the entrainment are discussed, including the possible role of cryptochromes.

scholarly journals Magnetic fluctuations affect circadian patterns of locomotor activity in zebrafish

2021 ◽  
Author(s):  
Viacheslav V. Krylov ◽  
Evgeny I. Izvekov ◽  
Vera V. Pavlova ◽  
Natalia A. Pankova ◽  
Elena A. Osipova
Keyword(s):  
Magnetic Field ◽  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Danio Rerio ◽  
Magnetic Fluctuations ◽  
Constant Illumination ◽  
Free Running ◽  
Circadian Patterns

AbstractThe locomotor activity of zebrafish (Danio rerio) has a pronounced, well-studied circadian rhythm. Under constant illumination, the period of free-running locomotor activity in this species usually becomes less than 24 hours. To evaluate the entraining capabilities of slow magnetic variations, zebrafish locomotor activity was evaluated at constant illumination and fluctuating magnetic field with a period of 26.8 hours. Lomb-Scargle periodogram revealed significant free-running rhythms of locomotor activity and related behavioral endpoints with a period close to 27 hours. Obtained results reveal the potential of slow magnetic fluctuations for entrainment of the circadian rhythms in zebrafish. The putative mechanisms responsible for the entrainment are discussed, including the possible role of cryptochromes.

Effects of aging on entrainment and rate of resynchronization of circadian locomotor activity

1992 ◽  
Vol 263 (5) ◽  
pp. R1099-R1103 ◽  
Author(s):  
P. C. Zee ◽  
R. S. Rosenberg ◽  
F. W. Turek
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Activity Rhythm ◽  
Phase Advance ◽  
Middle Aged ◽  
Age Related ◽  
Free Running ◽  
Effects Of Aging ◽  
Free Running Period ◽  
Related Phase

The phase angle of entrainment of the circadian rhythm of the locomotor activity rhythm to a light-dark (LD) cycle was examined in young (2-5 mo old) and middle-aged (13-16 mo old) hamsters. An age-related phase advance in the onset of locomotor activity relative to lights off was seen during stable entrainment to a 14:10-h LD cycle. In addition, the effects of age on the rate of reentrainment of the circadian rhythm of locomotor activity were examined by subjecting young and middle-aged hamsters to either an 8-h advance or delay shift of the LD cycle. Middle-aged hamsters resynchronized more rapidly after a phase advance of the LD cycle than did young hamsters, whereas young hamsters were able to phase delay more rapidly than middle-aged hamsters. The age-related phase advance of activity onset under entrained conditions, and the alteration of responses in middle-aged hamsters reentraining to a phase-shifted LD cycle, may be due to the shortening of the free-running period of the circadian rhythm of locomotor activity with advancing age that has previously been observed in this species.

Rhythmic thermoregulation in larval cranefly (Diptera: Tipulidae)

1981 ◽  
Vol 59 (3) ◽  
pp. 555-558 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Circadian Rhythm ◽  
Thermal Gradient ◽  
Fourth Instar ◽  
Behavioural Thermoregulation ◽  
Dark Cycle ◽  
Constant Illumination ◽  
Temperature Selection ◽  
Preferred Temperatures ◽  
Free Running ◽  
Maximum Temperatures

The behaviour of fourth-instar larvae of a cranefly Tipula plutonis was examined in a horizontal thermal gradient. Under a 12 h light: 12 h dark cycle, larvae displayed a diel rhythm of preferred temperatures. Maximum temperatures (16–18 °C) were selected during the scotophase and minimum temperatures (12–14 °C) were selected during the photophase of the light–dark cycle. Under constant illumination, temperature selection continued as an endogenous free-running circadian rhythm of behavioural thermoregulation.

Circadian rhythms of rabbits during restrictive feeding

1987 ◽  
Vol 253 (1) ◽  
pp. R46-R54 ◽  
Author(s):  
B. Jilge ◽  
H. Hornicke ◽  
H. Stahle
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Food Access ◽  
Feeding Time ◽  
Restricted Feeding ◽  
Small Component ◽  
Physiological Functions ◽  
System A ◽  
Free Running

Without a zeitgeber the circadian rhythms of five physiological functions free-ran with a period length greater than 24 h. Restricted feeding time (RF) masked the free-running rhythms. In addition to masking, entrainment with RF occurred. This process was most evident in locomotor activity and visits to the food box. RF thus had zeitgeber properties in these rabbits. However, in most rabbits the RF zeitgeber was not strong enough to entrain the circadian rhythm completely. A small component free-ran during RF. Following return to continuous food access the whole circadian rhythm resumed to free-run again. In some animals its phase was determined by the RF zeitgeber and in others by the small free-running fraction present during RF. The results suggest that in addition to the light-dark-entrainable circadian oscillator system a feeding-entrainable oscillator exists that takes over phase control of the majority of the rhythm during RF.

Endogenous ultradian rhythms in rats exposed to prolonged continuous light

1978 ◽  
Vol 235 (5) ◽  
pp. R250-R256 ◽  
Author(s):  
K. I. Honma ◽  
T. Hiroshige
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Continuous Light ◽  
Plasma Corticosterone ◽  
Ultradian Rhythm ◽  
Ultradian Rhythms ◽  
Serial Sampling ◽  
Free Running

Circadian rhythms of locomotor activity, body temperature, and plasma corticosterone were determined simultaneously in individual rats that were exposed to 200 lx continuous light for over 3 mo. Free-running circadian rhythms of locomotor activity persisted for about 2 mo under continuous light and then the rhythms gradually decomposed. After 3 mo of exposure, circadian rhythms disappeared and activity bursts of 1- to 2-h duration manifested themselves several times during a 24-h period. Body temperature also exhibited several bursts of fluctuation and these bursts were closely correlated in their temporal sequence with those of locomotor activity. A least-squares spectrum analysis revealed that the burst had regular 4- to 6-h periods. Plasma corticosterone, determined by serial sampling at 2-h intervals from individual rats, also exhibited several secretion episodes in a day. These episodic secretions synchronized with bursts of locomotor activity. These results suggest that the ultradian component, manifested under prolonged continuous light, is a fundamental unit of the circadian rhythm and an oscillator for the ultradian rhythm is common to the three functions examined.

Hemodynamic variability and circadian rhythm in rats with heart failure: role of locomotor activity

1993 ◽  
Vol 264 (6) ◽  
pp. H2111-H2118 ◽  
Author(s):  
J. R. Teerlink ◽  
J. P. Clozel
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Heart Rate ◽  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Power Spectral Analysis ◽  
Activity Level ◽  
Power Spectral ◽  
Coefficients Of Variation

Heart rate variability is known to be decreased by heart failure; however, the influences of concomitant diseases, changes in activity level, evolution through time, and abnormalities in the circadian rhythm are unknown. This study evaluated the influence of these factors by assessing hemodynamic variability in rats with heart failure (n = 8) and sham-operated controls (n = 8) through telemetric monitoring of heart rate, blood pressure, and locomotor activity for 8 wk. Hemodynamic variability was assessed by the standard deviation as well as hourly standard deviations and coefficients of variation of these variables over 48 h at 2, 4, and 8 wk after myocardial infarction. The circadian rhythm was investigated through power spectral analysis. Heart failure was associated with marked decreases in heart rate and mean arterial pressure variability and circadian rhythm without any differences in activity and no change through time. Heart failure in rats due to myocardial infarction in the absence of any confounding diseases is associated with marked abnormalities in hemodynamic variability and circadian rhythm independent of locomotor activity.

Hormonal and locomotor activity rhythms in rats under 90-min dark-pulse conditions

1993 ◽  
Vol 264 (6) ◽  
pp. R1058-R1064
Author(s):  
M. L. Laakso ◽  
T. Porkka-Heiskanen ◽  
L. Leinonen ◽  
S. L. Joutsiniemi ◽  
P. T. Mannisto
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Serum Levels ◽  
Thyroid Stimulating Hormone ◽  
Diurnal Variations ◽  
Serum Corticosterone ◽  
Pineal Melatonin ◽  
Free Running ◽  
Dark Pulse

The ability of a short dark pulse to entrain the circadian rhythms in rats was investigated. Pineal melatonin contents and serum levels of corticosterone and thyrotropin, a thyroid-stimulating hormone (TSH), were measured and locomotor activity was recorded under 12:12-h light-dark cycles (LD; darkness from 1800 to 0600 h) and under a 22.5:1.5 h LD lighting schedule (darkness from 1800 to 1930 h). The 90-min dark pulse was enough to trigger the rise of melatonin synthesis, but a free-running component was detected in the locomotor activity. Corticosterone levels showed diurnal variations under both conditions. The decrease of corticosterone and the increase of melatonin were phase locked, but the corticosterone pattern was distorted under the dark-pulse conditions. The 24-h rhythm of TSH was detectable in the control but not in the dark-pulse schedule. The results suggest that the circadian rhythm of pineal melatonin and the decrease of serum corticosterone levels were entrainable by the dark pulses, whereas the increase of corticosterone, the variations of TSH, and the rhythm of locomotor activity were not.

Effects of daily melatonin injections on activity rhythms of rats in constant light

1987 ◽  
Vol 253 (1) ◽  
pp. R101-R107 ◽  
Author(s):  
M. J. Chesworth ◽  
V. M. Cassone ◽  
S. M. Armstrong
Keyword(s):  
Locomotor Activity ◽  
Saline Solution ◽  
Constant Light ◽  
Constant Darkness ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Melatonin Administration ◽  
Free Running ◽  
Circadian Patterns ◽  
Phase Relationships

Although from pinealectomy studies the pineal body does not appear to participate in the generation of circadian rhythms of mammals, daily injections of the pineal hormone melatonin entrain free-running locomotor activity rhythms of rats in constant darkness. The aim of the present study was to determine whether rats whose circadian activity and drinking rhythms were disrupted in constant light (LL) could be synchronized by daily melatonin administration. Rats were subjected to a regime of gradually increasing photoperiod until they were maintained in LL. Rats whose rhythms became disrupted or showed intact free-running rhythms were injected daily with either melatonin (1 mg/kg) or vehicle (ethanol-saline) solution. Daily melatonin injections either synchronized or partly synchronized disrupted circadian patterns of activity. In contrast to previous findings from experiments conducted in constant darkness, melatonin did not entrain but only partly synchronized intact free-running rhythms. Results are interpreted in terms of melatonin acting on the coupling or phase relationships between oscillators generating circadian locomotor activity rhythms.

Sign in / Sign up

Export Citation Format

Share Document