Strain-differentiated circadian and ultradian rhythms in locomotor activity of the laboratory rat

Büttner, D.; Wollnik, Franziska

doi:10.1007/bf01076410

Cited by 66 publications

(36 citation statements)

References 20 publications

(13 reference statements)

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“…LEW rats showed a multimodal activity pattern with two rather short activity bouts about 3-5 hours apart from each other. Previous studies have shown a similar pattern in the daily rhythms o f overall activity as measured with an Animex-like svstem (7 ). body temperature and heart rate (6).…”

Section: Discuss Io!'-supporting

confidence: 59%

Wheel-running activity rhythms in two inbred strains of laboratory rats under different photoperiods

Siebert

Wollnik

1991

Physiology & Behavior

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SIEBERT, U. AND F. WOLLNIK. Wheel-running activity rhythms in two inbred strains of laboratory rats under different photoperiods. PHYSIOL BEHAV 50(6) 1137-1143, 1991.-Wheel-running activity patterns were studied in two inbred rat strains (ACI/Ztrn and LEW/Ztm) under 24-h light-dark cycles with various pbotoperiods. The ACI strain was characterized by a unimodal activity pattern, whereas the LEW strain exhibited a multimodal activity pattern consisting of two activity bouts about 3-5 h apart. Harmonic spectral analyses and chi square periodograms revealed strain-specific differences in the characteristic rhythmic components of the activity pattern. Tile ACI strain showed only a strong 24-h rhythm, whereas the LEW strain showed additional rhythmic components with periods of 6, 4.8, and 4 h. Except in very young rats, these strain specific patterns were not affected by an experimental lengthening of the dark period. However. differences between the two strains were found in the free-running period and in the mode of entrainment. Our results indicate that the multimodal activity pattern of the LEW strain is not due to an ultradian bout oscillator, instead it may be the result of a unique coupling of multiple circadian oscillators. Circadian and ultradian rhythmsStrain differences Entrainment Multioscillatory system

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Section: Discuss Io!'-supporting

confidence: 59%

Wheel-running activity rhythms in two inbred strains of laboratory rats under different photoperiods

Siebert

Wollnik

1991

Physiology & Behavior

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“…The origin of similar temporal variations on a smaUer time scale, caUed ultradian or short-term rhythms, remains unclear [11]. Ultradian rhythms in locomotor activity are known to exist in laboratory rats [8, 9, 2~30, 49], however, attracting much less attention than circadian rhythms.A recent study of LEW/Ztm rats has shown that ultradian rhythms of 4 and 4.8 hr periods are geneticaUy fixed in this Estradiol Testosterone inbred strain (9]. The persistence of these ultradian rhythms foUowing the disruption of circadian organization under continuous light supported the assumption that the activity rhythms of this strain are caused by an independent ultradian oscillator [9].…”

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confidence: 93%

Effects of adult or perinatal hormonal environment on ultradian rhythms in locomotor activity of laboratory LEW/Ztm rats

Wollnik

Döhler

1986

Physiology & Behavior

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. Effects of adult or perinatal hormonal environment on ultradian rhythms in locomotor activity of laboratory LEWIZtm rats. PHYSIOL BEHA V 38(2) [229][230][231][232][233][234][235][236][237][238][239][240] 1986.-Four experiments were performed with male and female rats of the inbred strain LEW/Ztm maintained under a light-dark schedule of 12: 12 hours. The animals were subject to castration CGOX) or ovariectomy (OVX), estradiol 17J3-implantation (E2-capsules), and perinatal hormonal treatments with testosterone propionate (TP) aod an androgen antagonist (cyproterone acetate, CA). Results indicated a difference in the locomotor activity pattern between the two sexes as a result of the endogenous estradiol levels of the adult animals. The activity pall ern of male LEW rats was characterized by ultradian rhythms of 4 and 4.8 hr periods. The female LEW rats, on the other hand, generally exhibited a clear circadian activity pattern and no uttradian activity rhythms. Following ovariectomy, each of the females showed distinct ultradian rhythms. These disappeared after E2-implantation. Castration of adult males had no effect on the ultradian activity pattern. Implantation of E2-capsules resulted in a marked decrease of the ultradian activity components. Perinatal treatment of the males with an androgen antagonist (CA) did not appear to effect ultradian rhythms during adulthood. Females treated perinatally with testosterone showed a significant increase in the ultradian activity components. This effect is assumed to be due to low estrogen levels in these animals during adulthood. Our study supports the assumption that ultradian rhythms are a result of changes in I he phase relationships between several circadian oscillators. The synchrony of these oscillations seems to be facilitated by estradiol. Ultradian rhythmsLocomotor activity Gonadectomy Brain differentiation Laboratory rat SEVERAL weU-known phenomena of circadian rhythms in mammals can be explained by the model of the circadian system as a composite of multiple, highly ordered oscillators [40][41][42]46]located in or close to the suprachiasmatic nuclei in the hypothalamus [47]. The origin of similar temporal variations on a smaUer time scale, caUed ultradian or short-term rhythms, remains unclear [11]. Ultradian rhythms in locomotor activity are known to exist in laboratory rats [8, 9, 2~30, 49], however, attracting much less attention than circadian rhythms.A recent study of LEW/Ztm rats has shown that ultradian rhythms of 4 and 4.8 hr periods are geneticaUy fixed in this Estradiol Testosterone inbred strain (9]. The persistence of these ultradian rhythms foUowing the disruption of circadian organization under continuous light supported the assumption that the activity rhythms of this strain are caused by an independent ultradian oscillator [9]. Alternatively, the persistence of ultradian rhythms can be explained by changes in the phase relationships between several circadian oscillators [46). The ultradian rhythms of the inbred strain LEW/Ztm are sex-specific, ...

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“…Measurements performed on rats of the BH and LEW strains under continuous light conditions confirmed the assumption of an independent ultradian oscillator which causes activity rhythms in the LEW and BH strains [7]. Other authors [13), however, suggest that ultradian rhythmicity reflects the activity of several circadian oscillators coupled to one another in various phase relations (i.e.…”

Section: Sex Differences In the Daily Pattern Of Locomotor Activity Imentioning

confidence: 64%

“…Ultradian rhythms, which have been found to be genetically fixed in two inbred strains of rats [7], are also sex-specific. They w~re observed in male animals of these strains.…”

Section: Sex Differences In the Daily Pattern Of Locomotor Activity Imentioning

confidence: 97%

“…Since ultradian rhythms in locomotor activity were observed only in male animals of the LEW and BH strains, the data additionally indicate that ultradian rhythms in locomotor activity are sex-specific. Ultradian rhythms are known to exist in laboratory rats (11,12], and it has been shown that their existence is connected with a distinct genetical background [7]. Causal and functional analyses of ultradian rhythms, however, have only just begun.…”

Section: Sex Differences In the Daily Pattern Of Locomotor Activity Imentioning

confidence: 99%

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Sex differences in the daily pattern of locomotor activity in laboratory rats

Wollnik

1985

Naturwissenschaften

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Strain-differentiated circadian and ultradian rhythms in locomotor activity of the laboratory rat

Abstract: Spontaneous locomotor activity (LA) was recorded in five inbred strains of laboratory rats (ACI/ZtmKEY WORDS: circadian and ultradian rhythms; strain differences; locomotor activity; laboratory rat.

Cited by 66 publications

References 20 publications

Wheel-running activity rhythms in two inbred strains of laboratory rats under different photoperiods

Wheel-running activity rhythms in two inbred strains of laboratory rats under different photoperiods

Effects of adult or perinatal hormonal environment on ultradian rhythms in locomotor activity of laboratory LEW/Ztm rats

Sex differences in the daily pattern of locomotor activity in laboratory rats

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