Cycle of lordosis behavior in female hamsters whose circadian activity rhythm has split into two components

1982 ◽  
Vol 243 (1) ◽  
pp. R112-R118 ◽  
Author(s):  
J. Swann ◽  
F. W. Turek
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Estrous Cycle ◽  
Activity Rhythm ◽  
Constant Light ◽  
Circadian Activity ◽  
Circadian Activity Rhythm ◽  
Activity Phase

Within 75 days of exposure to constant light (LL), the circadian activity rhythm of 21 of 32 hamsters had dissociated or "split" into two distinct components. These components were labeled either evening (E) or morning (M) depending on whether they appeared to be derived from the E or M portion of the activity phase prior to the occurrence of "splitting." Both regular (i.e., 4-day) and irregular (i.e., non-4-day) cycles in lordosis behavior were observed in all of the animals with an intact activity rhythm and in 18 of the 21 animals with a split rhythm of activity. The onset of behavioral estrus always occurred near the time of the onset of locomotor activity in animals with an intact activity rhythm. Among the females with a split activity rhythm, seven showed lordosis onsets only near the onset of the E component whereas five others began lordosis behavior only near the onset of the M component. Importantly, in five animals the onset of lordosis was associated on different days with either the E or M component. These results indicate that cycles in lordosis behavior persist even after the circadian rhythm of activity has dissociated into two components, and that at least one component of the estrous cycle, onset of lordosis behavior, can be coupled to either of two oscillators that underlie the circadian rhythm of locomotor activity in hamsters.

Photoperiodic time measurement and photoentrainment of a circadian locomotor activity rhythm in subtropical tree sparrows

2017 ◽  
Vol 16 (7) ◽  
pp. 1146-1152 ◽  
Author(s):  
Anand S. Dixit ◽  
Namram S. Singh ◽  
Iadalangki Bamon
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Activity Rhythm ◽  
Time Measurement ◽  
Circadian Activity ◽  
Tree Sparrow ◽  
Passer Montanus ◽  
Locomotor Activity Rhythm ◽  
Gonadal Growth ◽  
Endogenous Circadian Rhythm

Experiments were performed on the subtropical tree sparrow (Passer montanus) to investigate the involvement of an endogenous circadian rhythm in photoperiodic time measurement during the initiation of gonadal growth and functions and also to study the photic entrainment of the circadian activity rhythm.

A circadian rhythm in the locomotive behaviour of the giant garden slug Limax maximus

1977 ◽  
Vol 66 (1) ◽  
pp. 47-64
Author(s):  
P. G. Sokolove ◽  
C. M. Beiswanger ◽  
D. J. Prior ◽  
A. Gelperin
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Phase Angle ◽  
Circadian Rhythmicity ◽  
Constant Darkness ◽  
Light Cycle ◽  
Circadian Activity ◽  
Locomotor Rhythm ◽  
Activity Peak ◽  
Limax Maximus

The locomotor activity of the garden slug Limax maximus was examined for components of circadian rhythmicity. Behavioural (running wheel) studies clearly demonstrated that the activity satisfies the principal criteria of circadian rhythmicity. In constant darkness at a constant temperature, the locomotor activity freeran with a period of about 24 h (range 23-6-24-6 h). The rhythm was also expressed in constant light with a period for individual slugs that tended to be shorter in LL than in DD. The period of the rhythm was temperature compensated (11–5-21-5 degrees C) with a Q10 approximately equal to 1–00. The locomotor rhythm could be entrained to 24 h LD cycles such that the circadian activity peak occurred during the dark. The phase angle between the onset of activity and lights-off was not fixed, but was a function of the photoperiod of the entraining light cycle.

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.

Splitting of the locomotor activity rhythm in rats by exposure to continuous light

1983 ◽  
Vol 244 (4) ◽  
pp. R573-R576 ◽  
Author(s):  
Phyllis W. Cheung ◽  
Charles E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Estrous Cycle ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Female Rats ◽  
Locomotor Rhythm ◽  
Estrous Cycles ◽  
Locomotor Activity Rhythm ◽  
Active Portion ◽  
Free Running

Female rats exposed to low intensities (0.1–1.5 lx) of continuous light (LL), displayed regular estrous cycles and free-running circadian rhythms of locomotor activity. In most rats, as the intensity of LL was increased to >2.0 lx, components within the active portion (α) of the locomotor rhythm remained synchronized as the periodicity of the rhythm lengthened. However, in a few rats agr split into two components; one of which free-ran with a period shorter than 24 h, while the other free-ran with a period longer than 24 h. As soon as the two components became maximally separated they spontaneously rejoined. In most rats, estrous cycles ceased shortly after the intensity of LL was increased to >2.0 lx even though the locomotor activity rhythm retained its unsplit free-running nature. These observations suggest that the multiple oscillators that control the rhythms of locomotor activity and the estrous cycle are normally coupled to one another. In certain intensities of LL, these oscillators uncouple and free-run with different periodicities, a condition which causes estrous cycles to cease and sometimes produces a split locomotor activity rhythm. circadian rhythm; oscillators; estrous cycle Submitted on November 9, 1981 Accepted on October 11, 1982

Response of hamster circadian system to transitions between light and darkness

1986 ◽  
Vol 250 (4) ◽  
pp. R708-R711 ◽  
Author(s):  
H. E. Albers
Keyword(s):  
Activity Rhythm ◽  
Phase Shifts ◽  
Circadian System ◽  
Circadian Cycle ◽  
Circadian Activity ◽  
Syrian Hamsters ◽  
Circadian Activity Rhythm ◽  
Free Running ◽  
Activity Onset

The effects of exposure to sudden transitions from dark to light (DL) and light to dark (LD) were determined on the free-running circadian activity rhythm of Syrian hamsters. The activity rhythm was phase delayed by 1-2 h by DL transitions provided during the 12-h interval before activity onset (subjective day). In contrast, DL transitions produced phase advances of approximately 1 h 2-12 h after activity onset. LD transitions tended to produce phase advances throughout the circadian cycle. During the subjective day, LD transitions resulted in phase advances of up to 4 h. After the onset of activity, LD transitions produced phase advances of a lesser magnitude than during the subjective day. In addition, some phase delays were also observed. When the phase shifts produced by DL and LD transitions were combined additively these transitions could account for the phase shifts previously reported for brief pulses of light.

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