Multiple regulatory elements result in regional specificity in circadian rhythms of neuropeptide expression in mouse SCN

Silver, Rae; Sookhoo, Alicia I.; LeSauter, Joseph; Stevens, Paula; Jansen, Heiko T.; Lehman, Michael N.

doi:10.1097/00001756-199910190-00008

Cited by 88 publications

(99 citation statements)

References 19 publications

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“…With regard to chemoarchitecture, SCN cells are heterogeneous in their peptidergic content and distribution (Van den Pol, 1980; Van den Pol and Tsujimoto, 1985). AVP is found primarily in the dorsomedial SCN, whereas gastrin-releasing peptide and VIP cells lie in the ventrolateral SCN (Moore and Silver, 1998;Silver et al, 1999;Abrahamson and Moore, 2001;Moore et al, 2002). Of the calcium-binding proteins, calbindin is localized to the ventrolateral region of both the rat and hamster SCN and is sparsely distributed through the mouse SCN, whereas calretinin is found in the ventral mouse SCN and the lateral rat SCN and is sparsely distributed in the hamster SCN (Moore and Silver, 1998;Silver et al, 1999;Arvanitogiannis et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Phenotype Matters: Identification of Light-Responsive Cells in the Mouse Suprachiasmatic Nucleus

et al. 2004

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Section: Discussionmentioning

confidence: 99%

Phenotype Matters: Identification of Light-Responsive Cells in the Mouse Suprachiasmatic Nucleus

et al. 2004

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“…The SCN core is rich in vasoactive intestinal polypeptide (VIP) and gastrin-releasing peptide (GRP) in mouse, rat, and hamster (Morin et al 1992;Moore 1996;Abrahamson and Moore 2001). Other peptides in the SCN core, however, are more variable among species (Card and Moore 1984;Hartwich et al 1994;Silver et al 1999;Abrahamson and Moore 2001), likely reflecting functional species specializations. For example, the hamster core contains calbindin (CalB) and substance P (SP), whereas the mouse core contains calretinin and neurotensin.…”

Section: The Tissue Is the Issuementioning

confidence: 99%

Exploring Spatiotemporal Organization of SCN Circuits

Yan

Karatsoreos

LeSauter

et al. 2007

Cold Spring Harbor Symposia on Quantitative Biology

105

111

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Suprachiasmatic nucleus (SCN) neuroanatomy has been a subject of intense interest since the discovery of the SCN's function as a brain clock and subsequent studies revealing substantial heterogeneity of its component neurons. Understanding the network organization of the SCN has become increasingly relevant in the context of studies showing that its functional circuitry, evident in the spatial and temporal expression of clock genes, can be reorganized by inputs from the internal and external environment. Although multiple mechanisms have been proposed for coupling among SCN neurons, relatively little is known of the precise pattern of SCN circuitry. To explore SCN networks, we examine responses of the SCN to various photic conditions, using in vivo and in vitro studies with associated mathematical modeling to study spatiotemporal changes in SCN activity. We find an orderly and reproducible spatiotemporal pattern of oscillatory gene expression in the SCN, which requires the presence of the ventrolateral core region. Without the SCN core region, behavioral rhythmicity is abolished in vivo, whereas low-amplitude rhythmicity can be detected in SCN slices in vitro, but with loss of normal topographic organization. These studies reveal SCN circuit properties required to signal daily time.

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“…In hamsters, a dense population of the calcium-binding protein calbindin-D28k (CalB) cells also defines the core, whereas in mice, CalB is scattered throughout the SCN (24,31,32). In addition, cholecystokinin, somatostatin, and substance P neurons are present in several species (24,(32)(33)(34)(35). Given species differences, and the absence of strictly delineated areas (characteristic of other hypothalamic nuclei), broad generalizations about core and shell SCN regions can be ambiguous (36).…”

Section: Heterogeneity Of Scn Organization: Peptides and Clock Genesmentioning

confidence: 99%

Minireview: The Neuroendocrinology of the Suprachiasmatic Nucleus as a Conductor of Body Time in Mammals

Karatsoreos

Silver

2007

Endocrinology

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Circadian rhythms in physiology and behavior are regulated by a master clock resident in the suprachiasmatic nucleus (SCN) of the hypothalamus, and dysfunctions in the circadian system can lead to serious health effects. This paper reviews the organization of the SCN as the brain clock, how it regulates gonadal hormone secretion, and how androgens modulate aspects of circadian behavior known to be regulated by the SCN. We show that androgen receptors are restricted to a core SCN region that receives photic input as well as afferents from arousal systems in the brain. We suggest that androgens modulate circadian behavior directly via actions on the SCN and that both androgens and estrogens modulate circadian rhythms through an indirect route, by affecting overall activity and arousal levels. Thus, this system has multiple levels of regulation; the SCN regulates circadian rhythms in gonadal hormone secretion, and hormones feed back to influence SCN functions.For optimal function, organisms and cells must locate and operate in a defined temporal and spatial niche. The need for resource partitioning is obvious in the spatial domain and is also important in the temporal domain. The daily rising and setting of the sun provides a predictable environmental time cue to which organisms are sensitive. In mammals, a master circadian clock located in the suprachiasmatic nucleus (SCN) ensures that peripheral clocks throughout the brain and body function in the appropriate phase. Entrainment (synchronization to the environment) in mammalian systems involves the resetting of this master clock, which then communicates timing information to the rest of the body. In the absence of environmental cues, the internal clock runs at its endogenous, free-running period. This system permits the prediction of environmental changes while maintaining plastic responses to changes in the environment. SCN as Brain ClockEvidence that the SCN is the locus of a master circadian clock in mammals has been gathered over many years from many labs and entails methodologically distinct experimental paradigms with converging lines of evidence (1, 2). Briefly, lesions of the SCN result in a loss of all circadian rhythmicity in behavior and physiology, including hormone secretion. The SCN expresses rhythmic electrical and metabolic activity, even when placed in a dish in isolation from the rest of the brain (3, 4). After creation of a hypothalamic island containing the SCN, rhythmic electrical activity continues within the island (5), and hamsters bearing such hypothalamic islands continue to show rhythmic locomotor activity although the gonadal regression response to long-term constant darkness is lost (6). Transplantation of fetal hypothalamic tissue containing the SCN into the third ventricle of an SCN-lesioned animal restores circadian locomotor rhythms with a period reflecting that of the donor animal, but again, the gonadal regression response to constant darkness is lost (7,8). Interestingly, rhythms in hormone secretion are not restored by ...

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Multiple regulatory elements result in regional specificity in circadian rhythms of neuropeptide expression in mouse SCN

Cited by 88 publications

References 19 publications

Phenotype Matters: Identification of Light-Responsive Cells in the Mouse Suprachiasmatic Nucleus

Phenotype Matters: Identification of Light-Responsive Cells in the Mouse Suprachiasmatic Nucleus

Exploring Spatiotemporal Organization of SCN Circuits

Minireview: The Neuroendocrinology of the Suprachiasmatic Nucleus as a Conductor of Body Time in Mammals

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