Diurnal pattern of clock gene expression in the hypothalamus of the newborn rabbit

Caldelas, Ivette; Tejadilla, D.; González, Benjamín Zamudio; Montúfar, R.; Hudson, Robyn

doi:10.1016/j.neuroscience.2006.09.020

Cited by 26 publications

(26 citation statements)

References 53 publications

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“…Here, we extend our findings on the diurnal patterns of expression of clock genes in the SCN of the previsual newborn rabbit (Caldelas et al, 2007) by showing for the first time in this model that these represent endogenous rhythms, that the mother's daily nursing visit entrains the expression of three of these genes (Per1, Per2, and Bmal1), and in parallel with the entrainment of pups' daily rhythm in body temperature (Jilge et al, 2000. …”

Section: Introductionsupporting

confidence: 74%

“…To test whether the previously reported diurnal rhythm of clock gene expression in the SCN of neonatal rabbits (Caldelas et al, 2007) represents an endogenous circadian rhythm, we performed the following experiment. On P0 we formed nine litters culled to eight pups each.…”

Section: Fasted Pupsmentioning

confidence: 99%

“…Nevertheless, it is increasingly clear that to fully understand circadian function, and particularly in complex natural contexts, nonphotic input must also be considered (Hastings et al, 1997;Challet et al, 2003;Caldelas et al, 2005a). Although biologically relevant nonphotic stimuli are typically more difficult to identify, define and to administer than photic cues, a promising approach used increasingly in mammalian research is to study the develop-ment of circadian systems in previsual altricial young (Reppert, 1989;Escobar et al, 2000;Davis and Reppert, 2001;Jilge and Hudson, 2001;Shimomura et al, 2001;Ohta et al, 2002Ohta et al, , 2003Sládek et al, 2004;Caldelas et al, 2005aCaldelas et al, , 2007Kováîcikova et al, 2005Kováîcikova et al, , 2006Caba et al, 2008;reviewed in Caldelas et al, in press).…”

Section: Introductionmentioning

confidence: 99%

“…It is difficult, however, to investigate early circadian function in mammals without the confounding presence of the mother or other care-givers, whose near-continuous attention is usually necessary for survival of the young. A notable exception is the European rabbit (Oryctolagus cuniculus), whose unusually limited pattern of maternal care means that the altricial young can be observed and manipulated for long periods without maternal interference (Hudson and Distel, 1989;Hudson, 1998;Jilge and Hudson, 2001;Caldelas et al, 2005aCaldelas et al, , 2007.…”

Section: Introductionmentioning

confidence: 99%

“…As part of an on-going program investigating this we recently reported diurnal patterns in the expression of the clock genes Per1, Per2, Cry1, and Bmal1 in the suprachiasmatic nuclei of the hypothalamus (SCN; the main circadian pacemaker in mammals) (Caldelas et al, 2007). These genes are expressed abundantly in the SCN both of nocturnal and diurnal mammals (Reppert and Weaver, 2001;Honma et al, 2002;Caldelas et al, 2003), expression is modulated by both photic and nonphotic cues (Zylka et al, 1998;Challet et al, 2003;Caldelas et al, 2005b,c), and they are known to be major components of the molecular circadian clockwork Weaver, 2001, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Endogenous clock gene expression in the suprachiasmatic nuclei of previsual newborn rabbits is entrained by nursing

Caldelas

González

Montúfar-Chaveznava

et al. 2008

Developmental Neurobiology

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ABSTRACT:The rabbit is particularly suitable for investigating the development of mammalian circadian function. Blind at birth, the pups are only visited by the mother to be nursed once every 24 h for about 3 min and so can be studied largely without maternal interference. They anticipate the mother's visit with increased behavioral arousal and with a rise in body temperature, both of which represent endogenous circadian rhythms. We now report that in newborn pups the suprachiasmatic nuclei of the hypothalamus (SCN; the main circadian pacemaker in mammals) show endogenous 24-h rhythmicity in the expression of the clock genes Per1, Per2, and Bmal1. Pups nursed from postnatal days 1 to 7 and fasted to day 9 showed the same rhythms of clock gene expression as normally nursed controls. We also report that these rhythms are entrained by nursing.Pups killed on postnatal days 3-4 showed the same rhythms in gene expression as pups in the previous experiment, whereas littermates subsequently nursed from postnatal days 4 to 7 with nursing delayed 6 h showed a corresponding shift in the diurnal pattern of clock gene expression. Consistent with this, two groups of pups implanted with telemetric thermal sensors and nursed 6 h apart had daily patterns in body temperature synchronized with the two different nursing times. We conclude that the expression of clock genes associated with the newborn rabbit's circadian system is entrained by nonphotic cues accompanying nursing, the exact nature of which now needs to be clarified. '

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Section: Introductionsupporting

confidence: 74%

Section: Fasted Pupsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Endogenous clock gene expression in the suprachiasmatic nuclei of previsual newborn rabbits is entrained by nursing

Caldelas

González

Montúfar-Chaveznava

et al. 2008

Developmental Neurobiology

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Circadian clocks during embryonic and fetal development

Serón-Ferré

Valenzuela

Torres-Farfán

2007

Birth Defects Research Pt C

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Circadian rhythmicity is a fundamental characteristic of organisms, which helps ensure that vital functions occur in an appropriate and precise temporal sequence and in accordance with cyclic environmental changes. Living beings are endowed with a system of biological clocks that measure time on a 24-hr basis, termed the circadian timing system. In mammals, the system is organized as a master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus, commanding peripheral clocks located in almost every tissue of the body. At the cell level, interlocking transcription/translation feedback loops of the genes Bmal-1, Clock, Per1-2, and Cry1-2, named clock genes, and their protein products results in circadian oscillation of clock genes and of genes involved in almost every cellular function. During gestation, the conceptus follows a complex and dynamic program by which it is simultaneously fit to develop and live in a circadian environment provided by its mother and to prepare for the very different environment that it will experience after birth. It has been known for a number of years that the mother tells the fetus the time of day and season of the year, and that the fetus uses this information to set the phase of fetal and neonatal circadian rhythms. There is evidence that the maternal rhythm of melatonin is one of the time signals to the fetus. In the last few years, the study of the development of the circadian system has turned to the investigation of the oscillatory expression of clock genes and their possible role in development, and to answering questions on the organization of the fetal circadian system. Emerging evidence shows that clock genes are expressed in the oocyte and during early and late development in embryo/fetal organs in the rat and in a fetal primate. The data available raise the intriguing possibility that the fetal SCN and fetal tissues may be peripheral clocks commanded by separate maternal signals. The rapid methodological and conceptual advances on chronobiology may help to unravel how the developing embryo and fetus faces time in this plastic period of life.

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