Vasoactive intestinal peptide (VIP)-like immunoreactive neurons located in the rat suprachiasmatic nucleus receive a direct retinal projection

Ibata, Yasuhiko; Takahashi, Yukio; Okamura, Hitoshi; Kawakami, Fumio; Terubayashi, H; Kubo, Toshikazu; Yanaihara, Noboru

doi:10.1016/0304-3940(89)90129-8

Cited by 171 publications

(69 citation statements)

References 15 publications

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“…RHT fibers synapse onto VIP cells and GRP cells (rat; Ibata et al 1989; aspects of SCN circuits are consistent with these properties. For other aspects, particularly the function of the SCN in representing the time of day and season of the year, the evidence of spatiotemporal organization reviewed in this chapter is more consistent with a locally connected network in which signals spread rather slowly from one layer of connected nodes to the next.…”

Section: The Tissue Is the Issuementioning

confidence: 65%

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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Section: The Tissue Is the Issuementioning

confidence: 65%

Exploring Spatiotemporal Organization of SCN Circuits

Yan

Karatsoreos

LeSauter

et al. 2007

Cold Spring Harbor Symposia on Quantitative Biology

105

111

View full text Add to dashboard Cite

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“…This finding contrasts with data from the rat and mouse where retinal terminals are characterized by the presence of lucent mitochondria and make predominantly axo-dendritic and asymmetrical synapses (Guldner, 1978a(Guldner, , 1978bCard and Moore, 1991;Castel et al, 1993;Tanaka et al, 1997). It should be noted that axo-somatic symmetrical retinal synapses have also been described in these species.Given that the retinorecipient area of the hamster SCN is more extensive than the CaBP-ir subnucleus, it is clear that other neuronal subpopulations within the SCN also receive retinal (Ibata et al, 1989;Tanaka et al, 1993). The data suggest that the ultrastructural morphology of retinal input into the SCN varies with "peptidergic phenotype" in various rodent species.…”

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confidence: 94%

Retinal Innervation of Calbindin-D28K Cells in the Hamster Suprachiasmatic Nucleus: Ultrastructural Characterization

et al. 2000

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The authors have described a subregion of the hamster hypothalamic suprachiasmatic nucleus (SCN) containing cells that are immunopositive for the cytosolic calcium-binding protein, Calbindin-D 28K (CaBP). Several lines of evidence indicate that this region may constitute the site of the pacemaker cells that are responsible for the regulation of circadian locomotor rhythms. First, 79% of the CaBP-immunoreactive (ir) neurons express Fos in response to photic stimulation, indicating that they are close to or part of the input pathway to pacemakers. Second, at the light microscopy level, retinal terminals innervate the CaBP subnucleus. Finally, destruction of this subnucleus renders animals arrhythmic in locomotor activity. In this study, the authors examined the ultrastructural relationship between cholera toxin (CTβ) labeled retinal fibers and the CaBP-ir subregion within the hamster SCN. CTβ-ir retinal terminals make primarily axo-somatic, symmetric, synaptic contacts with CaBP-ir perikarya. In addition, retinal terminals form synapses with CaBP processes as well as with unidentified profiles. There are also complex interactions between retinal terminals, CaBP perikarya, and unidentified profiles. Given that axo-somatic synaptic input has a more potent influence on a cell's electrical activity than does axo-dendritic synaptic input, cells of the CaBP subregion of the SCN are ideally suited to respond rapidly to photic stimulation to reset circadian pacemakers.Keywords calcium-binding proteins; calbindin-D 28K ; CaBP; pacemaker; suprachiasmatic nucleus; retinal terminals; electron microscopy; circadian rhythmsThe suprachiasmatic nucleus (SCN) of the hypothalamus is the site of the putative circadian clock in mammals (see Klein et al., 1991). The circadian system regulates the periodicity of many rhythmic responses in mammals including rest-wake cycles (see Moore-Ede et al., 1982), electrical activity, and neuropeptide levels (Inouye, 1996), to name a few. In the absence of exogenous stimuli, the circadian clock oscillates with a periodicity that is close to 24 h. The circadian timing system also has the capacity to entrain or synchronize the organism to the exogenous geo-solar cycle. The primary neural substrate responsible for the © 2000 Sage Publications, Inc.Correspondence to: Maria-Teresa Romero. transduction of exogenous photic stimuli is the retinohypothalamic tract (RHT), a monosynaptic pathway projecting from the retina to the SCN (Card and Moore, 1991;Moore, 1996). A secondary pathway, the geniculo-hypothalamic tract, also provides photic input to the circadian pacemaker. Photic information is integrated in the SCN to produce a stable phase relationship between physiological and behavioral activity and the environmental light-dark cycle (Meijer, 1991). While it is clear that the SCN is the site of the circadian pacemaker, the precise identity of retinorecipient cells that mediate entrainment remains to be elucidated. NIH Public AccessWe recently described cells immunopositive for Calbindin-D 28K (...

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“…Since we observed compartmental (22) and highly organized interrelationship (9)(10)(11)21) of neurons in the nbcleus in vivo, we speculate that the intranuclear neuronal network formed by compactly packed neurons might be especially important in expressing the function of SCN. Thus, to elucidate the neuronal network involved in the circadian rhythm and its entrainment, an in vitro system should be developed which enables the observation of the rhythmic activity for a long time with the preservation of the intercellular neuronal network similar to that in vivo.…”

mentioning

confidence: 84%