Free-running circadian rhythm in wood mouse (Apodemus flavicollis Melch.) under natural light-dark-cycle

1969 ◽  
Vol 25 (6) ◽  
pp. 649-649 ◽  
Author(s):  
E. Erkinaro
Keyword(s):  
Circadian Rhythm ◽  
Wood Mouse ◽  
Natural Light ◽  
Apodemus Flavicollis ◽  
Dark Cycle ◽  
Free Running

Cortisol-mediated synchrinization of circadian rhythm in urinary potassium excretion

1977 ◽  
Vol 233 (5) ◽  
pp. R230-R238 ◽  
Author(s):  
M. C. Moore-ede ◽  
W. S. Schmelzer ◽  
D. A. Kass ◽  
J. A. Herd
Keyword(s):  
Circadian Rhythm ◽  
Saimiri Sciureus ◽  
Potassium Excretion ◽  
Dark Cycle ◽  
Urinary Potassium ◽  
Timing System ◽  
Daily Dose ◽  
Circadian Timing System ◽  
Free Running ◽  
Renal Potassium Excretion

Conscious chair-acclimatized squirrel monkeys (Saimiri sciureus) studied with lights on (600 lx) from 0800 to 2000 h daily (LD 12:12) display a prominent circadian rhythm in renal potassium excretion. The characteristics of this rhythm were reproduced in adrenalectomized monkeys by infusing 5 mg cortisol and 0.001 mg aldosterone, or 5 mg cortisol alone, between 0800 and 0900 h daily. When the timing of cortisol adminisration (with or without aldosterone) was phase-delayed by 8 h, the urinary potassium rhythm resynchronized by 80% of the cortisol phase shift, but only after a transient response lasting 3–4 days. With the same daily dose of adrenal steroids given as a continuous infusion throughout each 24 h, urinary potassium excretion showed free-running oscillations no longer synchronized to the light-dark cycle. These results indicate that the cirdacian rhythm of plasma cortisol concentration acts as an internal mediator in the circadian timing system, synchronizing a potentially autonomous oscillation in renal potassium excretion to environmental time cues and to other circadian rhythms within the animal.

A circadian rhythm of behavioural thermoregulation in a freshwater gastropod, Helisoma trivolis

1980 ◽  
Vol 58 (11) ◽  
pp. 2152-2155 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Circadian Rhythm ◽  
Constant Darkness ◽  
Dark Phase ◽  
Behavioural Thermoregulation ◽  
Dark Cycle ◽  
Preferred Temperature ◽  
Temperature Selection ◽  
Freshwater Gastropod ◽  
Free Running ◽  
Maximum Temperatures

The behaviour of the aquatic gastropod Helisoma trivolis was examined in a thermal gradient. Under a 12 h light: 12 h dark cycle gastropods displayed a diel rhythm of preferred temperature selection. Maximum temperatures (21–22 °C) were selected during the dark phase and minimum temperatures (17–18 °C) were selected during the light phase of the light–dark cycle. Under constant darkness temperature selection continued as an endogenous free-running circadian rhythm of behavioural thermoregulation.

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.

Are membrane properties essential for the circadian rhythm of Gonyaulax?

1984 ◽  
Vol 247 (2) ◽  
pp. R250-R256
Author(s):  
H. G. Scholubbers ◽  
W. Taylor ◽  
L. Rensing
Keyword(s):  
Circadian Rhythm ◽  
Phase Shift ◽  
Fluorescence Polarization ◽  
The Other ◽  
Membrane Properties ◽  
Response Curves ◽  
Whole Cells ◽  
Different Temperatures ◽  
Free Running ◽  
Free Running Period

Membrane properties of whole cells of Gonyaulax polyedra were measured by fluorescence polarization. Circadian changes of fluorescence polarization exist in exponentially growing cultures. They show an amplitude larger than that of stationary cultures, indicating that a part of the change is due to or amplified by an ongoing cell cycle. Measurements of parameters of the circadian glow rhythm were analyzed for possible correlation with the membrane data. Considerable differences (Q10 = 2.5-3.0) in fluorescence polarization were found in cultures kept at different temperatures ranging from 15 to 27.5 degrees C. The free-running period length at different temperatures, on the other hand, differed only slightly (Q10 = 0.9-1.1). Stationary cultures showed higher fluorescence polarization compared with growing cultures, whereas the free-running period lengths did not differ in cultures of various densities and growth rates. Temperature steps of different sign changed the fluorescence polarization slightly in different directions. The phase shift of 4-h pulses (-5, -9, +7 degrees C) resulted in maximal phase advances of 4, 6, and 2 h, respectively. The phasing of the phase-response curves was identical in all these experiments, a finding not to be expected if the pulses act via the measured membrane properties. Pulses of drugs that change the fluorescence polarization (e.g., chlorpromazine and lidocaine) did not or only slightly phase-shift the circadian rhythm.

Field identification of Apodemus flavicollis and Apodemus sylvaticus: a quantitative comparison of different biometric measurements

Mammalia ◽  
2016 ◽  
Vol 80 (5) ◽  
Author(s):  
Paola Bartolommei ◽  
Giulia Sozio ◽  
Cristina Bencini ◽  
Carlo Cinque ◽  
Stefania Gasperini ◽  
...  
Keyword(s):  
Wood Mouse ◽  
Apodemus Sylvaticus ◽  
Quantitative Comparison ◽  
Apodemus Flavicollis ◽  
Field Identification ◽  
Biometric Measurements

AbstractThe identification of the wood mouse

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.

scholarly journals Regulation of GLUT5 gene expression in rat intestinal mucosa: regional distribution, circadian rhythm, perinatal development and effect of diabetes

1995 ◽  
Vol 309 (1) ◽  
pp. 271-277 ◽  
Author(s):  
A Castelló ◽  
A Gumá ◽  
L Sevilla ◽  
M Furriols ◽  
X Testar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Intestine ◽  
Circadian Rhythm ◽  
Intestinal Absorption ◽  
Light Period ◽  
Proximal Jejunum ◽  
Mrna Levels ◽  
Dark Cycle ◽  
Perinatal Development ◽  
Streptozotocin Induced Diabetes

1. GLUT5 gene expression was studied in small intestine under a variety of conditions characterized by altered intestinal absorption of monosaccharides. 2. RNA-blotting studies showed that GLUT5 mRNA was abundantly expressed in rat and rabbit intestine and kidney, but it was not detected in heart or brown adipose tissue. GLUT5 mRNA levels were higher in the upper segments of the small intestine (duodenum and proximal jejunum) than in the lower segments (distal jejunum and ileum). 3. The intestinal expression of GLUT5 mRNA in rat proximal jejunum showed circadian rhythm. A 12-fold increase in GLUT5 mRNA levels was detected at the end of the light cycle and at the beginning of the dark cycle when compared with the early light period. In keeping with this, GLUT5 protein content in brush-border membranes was also increased at the beginning of the dark cycle compared with that in the light period. 4. In streptozotocin-induced diabetes an 80% increase in GLUT5 mRNA levels in mucosa from the proximal jejunum was detected under conditions in which enhanced intestinal absorption of monosaccharides has been reported. 5. The intestinal expression of GLUT5 mRNA showed regulation during perinatal development. Levels of GLUT5 mRNA were low during fetal life, increased progressively during the postnatal period and reached levels comparable with the adult state after weaning. Weaning on to a high-fat diet partially prevented the induction of GLUT5 gene expression. 6. Our results indicate that GLUT5 gene expression is tightly regulated in small intestine. Regulation involves maximal expression in the upper part of the small intestine, circadian rhythm, developmental regulation dependent on the fat and carbohydrate content in the diet at weaning and enhanced expression in streptozotocin-induced diabetes. Furthermore, changes observed in intestinal GLUT5 expression correlate with reported alterations in intestinal absorption of fructose. This suggests a regulatory role for GLUT5 in fructose uptake by absorptive enterocytes.

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