Loss of a circadian adrenal corticosterone rhythm following suprachiasmatic lesions in the rat

Moore, Robert Y.; Eichler, Victor B.

doi:10.1016/0006-8993(72)90054-6

Cited by 1,902 publications

(960 citation statements)

References 7 publications

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“…A highly localized brain clock in mammals was first suggested in 1972, with the demonstration that lesions ablating the SCN abolish circadian rhythmicity in adrenal corticoid secretion and locomotor behavior (Moore and Eichler, 1972;Stephan and Zucker, 1972). SCN-lesioned animals continue to show the full range of normal behaviors, but their temporal organization is lost and never recovers, irrespective of how early in development the lesions are performed (Mosko and Moore, 1979).…”

Section: Identification Of a Brain "Clock": From Tissue To Genementioning

confidence: 99%

“…Although capable of oscillating independently, these neuroendocrine cells respond to periodic SCN input to maintain a synchronized rhythm in the local cell population. Such mechanism could account for the loss of coherent circadian endocrine rhythms following lesions or transection of outputs from the SCN (Meyer-Bernstein et al, 1999;Moore and Eichler, 1972;Nunez and Stephan, 1977). Loss of coherence among elements would result in a blunted overall output and absence of rhythmicity when individual cells drift out of phase with each other.…”

Section: Clocks In the Neuroendocrine Systemmentioning

confidence: 99%

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The regulation of neuroendocrine function: Timing is everything

Kriegsfeld

Silver

2006

Hormones and Behavior

129

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Hormone secretion is highly organized temporally, achieving optimal biological functioning and health. The master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus coordinates the timing of circadian rhythms, including daily control of hormone secretion. In the brain, the SCN drives hormone secretion. In some instances, SCN neurons make direct synaptic connections with neurosecretory neurons. In other instances, SCN signals set the phase of "clock genes" that regulate circadian function at the cellular level within neurosecretory cells. The protein products of these clock genes can also exert direct transcriptional control over neuroendocrine releasing factors. Clock genes and proteins are also expressed in peripheral endocrine organs providing additional modes of temporal control. Finally, the SCN signals endocrine glands via the autonomic nervous system, allowing for rapid regulation via multisynaptic pathways. Thus, the circadian system achieves temporal regulation of endocrine function by a combination of genetic, cellular, and neural regulatory mechanisms to ensure that each response occurs in its correct temporal niche. The availability of tools to assess the phase of molecular/cellular clocks and of powerful tract tracing methods to assess connections between "clock cells" and their targets provides an opportunity to examine circadian-controlled aspects of neurosecretion, in the search for general principles by which the endocrine system is organized. KeywordsCircadian; Diurnal; Endocrinel; Neurosecretion; Clock genes; Suprachiasmatic Circadian aspects of reproductionThe importance of circadian (about a day) timing in hormone production/secretion has been known since the 1950s when Everett and Sawyer determined that a stimulatory signal occurring during a narrow temporal window on the afternoon of proestrus is necessary for induction of ovulation later that night (Everett and Sawyer, 1950). Such close temporal organization is important for successful reproduction, as numerous hormone-dependent behavioral and physiological processes must be coordinated. If optimal temporal relationships are disrupted, pronounced deficits in fertility can result. For example, ovulation, behavioral estrus, fertilization, and pregnancy maintenance require a specific

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Section: Identification Of a Brain "Clock": From Tissue To Genementioning

confidence: 99%

Section: Clocks In the Neuroendocrine Systemmentioning

confidence: 99%

The regulation of neuroendocrine function: Timing is everything

Kriegsfeld

Silver

2006

Hormones and Behavior

129

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“…In mammals, this rhythm is controlled by a master clock, which is localized in the suprachiasmatic nuclei (SCN) of the anterior-ventral hypothalamus (Moore and Eichler 1972;Stephan and Zucker 1972). Members of the Period gene family, Per1 and Per2 are key players in the underlying molecular mechanisms of the master clock Tei et al 1997).…”

Section: Introductionmentioning

confidence: 99%

“…The daily variation in the activity of the HPA axis, which is measured as abundance of plasma glucocorticoids (GCs) is under clock control (Moore and Eichler 1972;Kalsbeek and Buijs 2002). The daily peak of GCs is mainly mediated by a time-of-day dependent sensitivity to adrenocorticotropic hormone (ACTH) of the adrenal cortex (Kalsbeek et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Impaired daily glucocorticoid rhythm in Per1 Brd mice

et al. 2006

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Biological clocks have evolved in all kinds of organisms in order to anticipate and adjust to the daily light-dark cycle. Within the last decade, the molecular machinery underlying the circadian system was unraveled. In the present study, the impact of the loss of the Per1 or Per2 genes, key components of the core clock oscillator, on body mass, food and water intake, glucose metabolism, and hypothalamic-pituitary-adrenal axis, was investigated in the Per1 Brd and Per2 Brd mouse models. The results reveal that the lack of Per1 but not Per2 has severe consequences for the regulation of these parameters. Specifically, in Per1 Brd animals, we found an impaired daily glucocorticoid rhythm, with markedly elevated levels during the day compared to control animals. In addition, Per1 Brd mice showed significant differences in body mass as well as food and water intake. Although the Per1 Brd are lighter than wildtype mice, food and water intake per gram body mass is elevated. In addition, the Per1 Brd mice exhibit an increased glucose metabolism after i.p. injection with glucose. In conclusion, our study presents first evidence for a link between an altered metabolism in Per1 and Per2 deficient mice, which in the case of the Per1 Brd animals might be due to an impaired corticosterone rhythm.

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“…The SCN is located above the optic chiasm and receives direct projections from the retina, providing a pathway by which the clock could be entrained by light in the organism's environment (Moore, 1973). Moore and Eichler (1972) also demonstrated that when the SCN is lesioned, mice become arrhythmic. At the time there was uncertainty as to whether circadian rhythms in mammals resulted from molecular processes within individual cells, such as discussed in the previous section, or from an interaction of multiple cells organized together to generate oscillations.…”

Section: Integrating Intracellular Operations Into An Intercellular Nmentioning

confidence: 99%

Mechanists Must be Holists Too! Perspectives from Circadian Biology

Bechtel

2016

J Hist Biol

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The pursuit of mechanistic explanations in biology has produced a great deal of knowledge about the parts, operations, and organization of mechanisms taken to be responsible for biological phenomena. Holist critics have often raised important criticisms of proposed mechanistic explanations, but until recently holists have not had alternative research strategies through which to advance explanations. This paper argues both that the results of mechanistic strategies has forced mechanists to confront ways in which whole systems affect their components and that new representational and modeling strategies are providing tools for understanding these effects of whole systems upon components. Drawing from research on the mechanism responsible for circadian rhythms in mammals, I develop two examples in which mechanistic analysis is being integrated into a more holist perspective: research revealing intercellular integration of circadian mechanisms with those involved in cell metabolism and research revealing that stable rhythms are dependent on how individual cells in the suprachiasmatic nucleus synchronize with each other to generate regular rhythms. Tools such as network diagramming and computational modeling are providing means to integrate mechanistic models into accounts of whole systems.

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Loss of a circadian adrenal corticosterone rhythm following suprachiasmatic lesions in the rat

Cited by 1,902 publications

References 7 publications

The regulation of neuroendocrine function: Timing is everything

The regulation of neuroendocrine function: Timing is everything

Impaired daily glucocorticoid rhythm in Per1 Brd mice

Mechanists Must be Holists Too! Perspectives from Circadian Biology

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