scholarly journals Circatidal activity rhythm in the mangrove cricket Apteronemobius asahinai

2008 ◽  
Vol 4 (3) ◽  
pp. 233-236 ◽  
Author(s):  
Aya Satoh ◽  
Eiji Yoshioka ◽  
Hideharu Numata
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
High Tide ◽  
Active Phase ◽  
Endogenous Rhythm ◽  
Constant Darkness ◽  
Mangrove Forests ◽  
Dark Cycle ◽  
Forest Floors ◽  
Free Running Period

Mangrove forests are influenced by tidal flooding and ebbing for a period of approximately 12.4 hours (tidal cycle). Mangrove crickets ( Apteronemobius asahinai ) forage on mangrove forest floors only during low tide. Under constant darkness, most crickets showed a clear bimodal daily pattern in their locomotor activity for at least 24 days; the active phases of approximately 10 hours alternated with inactive phases of approximately 2 hours, which coincided with the time of high tide in the field. The free-running period was 12.56±0.13 hours (mean±s.d., n =11). This endogenous rhythm was not entrained by the subsequent 24 hours light–dark cycle, although it was suppressed in the photophase; the active phase in the scotophase continued from the active phase in the previous constant darkness, with no phase shift. The endogenous rhythm was assumed to be a circatidal rhythm. On the other hand, the activity under constant darkness subsequent to a light–dark cycle was more intense in the active phase continuing from the scotophase than from the photophase of the preceding light–dark cycle; this indicates the presence of circadian components. These results suggest that two clock systems are involved in controlling locomotor activity in mangrove crickets.

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.

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 Entrainability of Locomotor Activity Rhythm to the Reversed Light-dark Cycle in the Hagfish.

1993 ◽  
Vol 59 (7) ◽  
pp. 1147-1150 ◽  
Author(s):  
Hiroshi Kabasawa ◽  
Sadako Ooka-Souda ◽  
Fumio Takashima
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
Dark Cycle ◽  
Locomotor Activity Rhythm

scholarly journals Short Neuropeptide F regulates the starvation mediated enhanced locomotor Activity in Drosophila

2019 ◽  
Author(s):  
Anna Geo ◽  
Himani Pathak ◽  
Anamika Elizabeth Kujur ◽  
Sreesha R Sudhakar ◽  
Nisha N Kannan
Keyword(s):  
Locomotor Activity ◽  
Circadian Clock ◽  
Internal Energy ◽  
Nutrient Availability ◽  
Activity Rhythm ◽  
Transcript Level ◽  
Constant Darkness ◽  
Starvation Resistance ◽  
Neuropeptide F

AbstractThe circadian clock regulates various behavioral, metabolic and physiological processes to occur at the most suitable time of the day. Internal energy stores and nutrient availability modulates the most apparent circadian clock mediated locmotor activity rhythm in Drosophila. Although previous studies unraveled the role of circadian clock in metabolism and activity rest rhythm, the precise pathway through which the circadian neuropeptidergic signaling regulates internal energy storage and the starvation-mediated increase in activity resembling foraging remains largely unclear. This study was aimed to elucidate the role of circadian neuropeptide, short neuropeptide F (sNPF) in triglyceride metabolism, starvation resistance and starvation-mediated increased locomotor activity in Drosophila. The results showed that snpf transcripts exhibits significant rhythmicity in wild type flies under 12:12 hour light-dark cycles (LD) and constant darkness (DD) whereas snpf transcript level in period null flies did not exhibit any significant rhythmicity under LD. Knockdown of sNPF in circadian clock neurons reduced the triglyceride level, starvation resistance and increased the starvation-mediated hyperactivity response after 24 hour of starvation. Further studies showed that knock down of sNPF receptors (sNPFR) expressed in insulin producing cells (IPC) increased the starvation resistance and reduced starvation-induced hyperactivity response after 24 hour of starvation. Collectively, our results suggest that transcriptional oscillation of snpf mRNA is endogenously controlled by the circadian clock and elucidate the role of sNPF in modulating locomotor activity in accordance with the nutrient availability in Drosophila.

Entrainment in calorie-restricted mice: conflicting zeitgebers and free-running conditions

1998 ◽  
Vol 274 (6) ◽  
pp. R1751-R1761 ◽  
Author(s):  
Etienne Challet ◽  
Leah C. Solberg ◽  
Fred W. Turek
Keyword(s):  
Locomotor Activity ◽  
Calorie Restriction ◽  
Phase Advance ◽  
Constant Darkness ◽  
Dark Cycle ◽  
Subjective Night ◽  
Ad Libitum ◽  
Anticipatory Activity ◽  
Time Of Feeding ◽  
Nocturnal Period

Phase-shifting effects of timed calorie restriction were investigated in mice during exposure to a 12:12-h light-dark cycle. Food-anticipatory activity (FAA), the output of a food-entrainable pacemaker, was expressed before the time of feeding whether mice received daily hypocaloric food (3.3 g of chow/day) or normocaloric food (5 g of chow/day) at zeitgeber time (ZT) 2 (ZT12 = lights off). Subsequently, mice were placed in constant darkness and fed ad libitum. The onset of the nocturnal period of locomotor activity was phase advanced by 1 h in calorie-restricted mice compared with normocalorie-fed controls. The phase advance still occurred when FAA was prevented by restraining calorie-restricted mice. Giving hypocaloric food at ZT2, ZT10, ZT14, or ZT22 phase advanced the nocturnal pattern of activity by 1, 3, 1, and 1 h, respectively. After transfer to constant darkness, FAA free ran in parallel with the normal nocturnal period of locomotor activity. A light pulse during the early subjective night phase delayed both components. These results indicate that 1) timed calorie restriction under a light-dark cycle can phase advance the light-entrainable pacemaker with a phase-dependent magnitude, 2) FAA feedback is not crucial for the observed phase advance, and 3) the light-entrainable pacemaker may control the period of the food-entrainable pacemaker in mice fed ad libitum.

REGULATION BY THE PITUITARY GLAND OF CIRCADIAN RHYTHMS IN THE HAMSTER

1980 ◽  
Vol 85 (1) ◽  
pp. 17-25 ◽  
Author(s):  
IRVING ZUCKER ◽  
CATHERINE P. CRAMER ◽  
E. L. BITTMAN
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Pituitary Gland ◽  
Activity Cycle ◽  
Active Phase ◽  
Circadian Oscillation ◽  
Constant Darkness ◽  
Subjective Night ◽  
The Difference

SUMMARY Locomotor activity of male hamsters was recorded during long-term exposure to constant light (LL), constant darkness (DD) and during entrainment (modification of a circadian rhythm) to a 14 h light: 10 h darkness photoperiod (14L: 10D). In LL the period of the activity cycle was substantially longer in hypophysectomized than in control animals. This difference persisted during tests in DD. Although hypophysectomy reduced the duration of the active phase in some hamsters, overall the difference between the groups was not significant. The phase angle of onset of activity in 14L: 10D was not affected by hypophysectomy. Hypophysectomized female hamsters tested in DD had activity rhythms whose periods were longer than those of control animals; they were also significantly less active than corresponding controls during the first 4 h of the subjective night but the duration of the active phase did not differ significantly between the groups. These results suggest that hormones of the pituitary-gonadal axis modulate the period of circadian oscillation.

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