scholarly journals Phase Resetting Light Pulses InducePer1and Persistent Spike Activity in a Subpopulation of Biological Clock Neurons

2003 ◽  
Vol 23 (4) ◽  
pp. 1441-1450 ◽  
Author(s):  
Sandra J. Kuhlman ◽  
Rae Silver ◽  
Joseph Le Sauter ◽  
Abel Bult-Ito ◽  
Douglas G. McMahon
Keyword(s):  
Spike Activity ◽  
Biological Clock ◽  
Phase Resetting ◽  
Light Pulses

Effect of somatostatin on circadian rhythms of firing and 2-deoxyglucose uptake in rat suprachiasmatic slices

1993 ◽  
Vol 265 (5) ◽  
pp. R1199-R1204 ◽  
Author(s):  
T. Hamada ◽  
S. Shibata ◽  
A. Tsuneyoshi ◽  
K. Tominaga ◽  
S. Watanabe
Keyword(s):  
Circadian Rhythm ◽  
Vasoactive Intestinal Polypeptide ◽  
Phase Changes ◽  
Circadian Clocks ◽  
Constant Darkness ◽  
Phase Resetting ◽  
Firing Activity ◽  
Light Pulses ◽  
Circadian Time

In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus appears to act as a circadian clock. The SCN vasoactive intestinal polypeptide-like immunoreactive neurons, which may act to mediate photic information in the SCN, receive input from neurons immunoreactive for somatostatin (SST). Therefore we investigated the role of SST as a transmitter for entrainment by analyzing the phase-resetting effect of SST on the circadian rhythm of SCN firing activity. Perfusion of SST increased 2-deoxyglucose uptake at circadian time (CT) 18, but not at CT6. A 1-h or 15-min treatment with SST produced phase delays when it was administered at CT13-14 and phase advances at CT22-23. Thus SST-induced phase changes are similar to those for light pulses to animals under constant darkness. The present findings suggest that SST is a transmitter for mediating information of entrainment to circadian clocks within the SCN.

Phase-resetting action of light on the circadian activity rhythm of Rattus exulans

1983 ◽  
Vol 245 (1) ◽  
pp. R10-R17
Author(s):  
P. H. Gander ◽  
R. D. Lewis
Keyword(s):  
Activity Rhythm ◽  
Phase Relationship ◽  
Masking Effect ◽  
Phase Resetting ◽  
Response Curves ◽  
Light Pulses ◽  
Subjective Night ◽  
Activity Onset ◽  
Effect Of Light

The phase resetting action of light on the circadian rhythm of locomotor activity has been examined in wild-caught Polynesian rats (Rattus exulans). Phase-response curves to 4-, 8-, and 16-h light pulses have been derived. All three curves conform to the generalization that pulses occurring during late subjective day and early subjective night produce delays, whereas advances occur in response to pulses coinciding with the late subjective night and early subjective day. Weak (type 1) phase resetting is observed in response to 4-h pulses and perhaps 8-h pulses, whereas strong (type 0) resetting apparently occurs in response to 16-h pulses. These data evidently constitute the first report of strong phase resetting in mammalian circadian rhythms. The phase relationship between an entrained activity rhythm and the light-dark cycle is dependent on the photoperiod and, in 24-h cycles, on the period difference between the rhythm and the zeitgeber. In longer zeitgeber cycles, activity onset is delayed by a direct masking effect of light. A primarily nonparametric action of light in natural entrainment is consistent with these data and with field observations.

Reduced glucose availability attenuates circadian responses to light in mice

1999 ◽  
Vol 276 (4) ◽  
pp. R1063-R1070 ◽  
Author(s):  
Etienne Challet ◽  
Susan Losee-Olson ◽  
Fred W. Turek
Keyword(s):  
Locomotor Activity ◽  
Glucose Utilization ◽  
Insulin Treatment ◽  
Phase Shifts ◽  
Constant Darkness ◽  
Phase Resetting ◽  
Light Pulses ◽  
Subjective Night ◽  
Saline Administration ◽  
Glucose Availability

To test whether circadian responses to light are modulated by decreased glucose availability, we analyzed photic phase resetting of the circadian rhythm of locomotor activity in mice exposed to four metabolic challenges: 1) blockade of glucose utilization induced by 2-deoxy-d-glucose (2-DG), 2) fasting (food was removed for 30 h), 3) insulin administration, and 4) insulin treatment after fasting. In mice housed in constant darkness, light pulses applied during early subjective night induced phase delays of the rhythm of locomotor activity, whereas light pulses applied during late subjective night caused phase advances. There was an overall reduction of light-induced phase shifts, with a more pronounced effect for delays, in mice pretreated with 500 mg/kg ip 2-DG compared with mice injected with saline. Administration of glucose with 2-DG prevented the reduction of light-induced phase delays. Furthermore, phase delays were reduced in fed mice pretreated with 5 IU/kg sc insulin and in fasted mice injected with saline or insulin compared with control fed mice. These results show that circadian responses to light are reduced when brain glucose availability is decreased, suggesting a metabolic modulation of light-induced phase shifts.

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.

Commentary: Strong or Weak Phase Resetting by Light Pulses in Humans?

1993 ◽  
Vol 8 (4) ◽  
pp. 348-350 ◽  
Author(s):  
Patricia L. Lakin-Thomas
Keyword(s):  
Phase Resetting ◽  
Light Pulses ◽  
Weak Phase

Strong or Weak Phase Resetting by Light Pulses in Humans?

1993 ◽  
Vol 8 (4) ◽  
pp. 340-347 ◽  
Author(s):  
Domien G. M. Beersma ◽  
Serge Daan
Keyword(s):  
Phase Resetting ◽  
Light Pulses ◽  
Weak Phase

scholarly journals Rapid Phase Resetting of a Mammalian Orcadian Rhythm by Brief Light Pulses

1998 ◽  
Vol 15 (6) ◽  
pp. 667-668
Author(s):  
Vijay Kumar Sharma ◽  
Maroli K. Chandrashekaren
Keyword(s):  
Phase Resetting ◽  
Rapid Phase ◽  
Light Pulses

Rapid Phase Resetting of a Mammalian Orcadian Rhythm by Brief Light Pulses

1997 ◽  
Vol 14 (6) ◽  
pp. 537-548 ◽  
Author(s):  
Vijay Kumar Sharma ◽  
Maroli K. Chandrashekaran
Keyword(s):  
Phase Resetting ◽  
Rapid Phase ◽  
Light Pulses

The brain structure and neurosecretory cells of noctuid moth Anadevidia peponis: Noctuidae

1990 ◽  
Vol 48 (3) ◽  
pp. 436-437
Author(s):  
M. Sato ◽  
Y. Ogawa ◽  
M. Sasaki ◽  
T. Matsuo
Keyword(s):  
Biological Clock ◽  
Virgin Female ◽  
Basic Structure ◽  
Fixed Time ◽  
Neurosecretory Cells ◽  
Nerve Cells ◽  
Noctuid Moth ◽  
The Right ◽  
20 Nm ◽  
The Brain

A virgin female of the noctuid moth, a kind of noctuidae that eats cucumis, etc. performs calling at a fixed time of each day, depending on the length of a day. The photoreceptors that induce this calling are located around the neurosecretory cells (NSC) in the central portion of the protocerebrum. Besides, it is considered that the female’s biological clock is located also in the cerebral lobe. In order to elucidate the calling and the function of the biological clock, it is necessary to clarify the basic structure of the brain. The observation results of 12 or 30 day-old noctuid moths showed that their brains are basically composed of an outer and an inner portion-neural lamella (about 2.5 μm) of collagen fibril and perineurium cells. Furthermore, nerve cells surround the cerebral lobes, in which NSCs, mushroom bodies, and central nerve cells, etc. are observed. The NSCs are large-sized (20 to 30 μm dia.) cells, which are located in the pons intercerebralis of the head section and at the rear of the mushroom body (two each on the right and left). Furthermore, the cells were classified into two types: one having many free ribosoms 15 to 20 nm in dia. and the other having granules 150 to 350 nm in dia. (Fig. 1).

The Biological Clock and Sleep in the Elderly

2006 ◽  
Vol 19 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Myriam Juda ◽  
Mirjam Münch ◽  
Anna Wirz-Justice ◽  
Martha Merrow ◽  
Till Roenneberg
Keyword(s):  
Circadian Rhythms ◽  
Biological Clock ◽  
The Elderly ◽  
Early Morning ◽  
Behavioral Changes ◽  
Older Age ◽  
Age Related ◽  
Theoretical Considerations ◽  
Sleep Difficulties ◽  
Circadian Biology

Abstract: Among many other changes, older age is characterized by advanced sleep-wake cycles, changes in the amplitude of various circadian rhythms, as well as reduced entrainment to zeitgebers. These features reveal themselves through early morning awakenings, sleep difficulties at night, and a re-emergence of daytime napping. This review summarizes the observations concerning the biological clock and sleep in the elderly and discusses the documented and theoretical considerations behind these age-related behavioral changes, especially with respect to circadian biology.

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