Expression of VIP and/or PACAP receptor mRNA in peptide synthesizing cells within the suprachiasmatic nucleus of the rat and in its efferent target sites

Κalamatianos, Theodosis; Kalló, Imre; Piggins, Hugh D.; Coen, Clive W.

doi:10.1002/cne.20168

Cited by 62 publications

(52 citation statements)

References 122 publications

(211 reference statements)

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“…4 A and E and Fig. S9), as previously shown (15). A confocal z-stack analysis using triple labeling for VIP, a presynaptic marker (synaptophysin), and retinal axonal CTβ fluorescence revealed potential synaptic contacts between retinal axons and VIP+ neurons (Fig.…”

Section: Retinal Projections To the Scn: Identification Of Postsynaptsupporting

confidence: 80%

“…VIP+ cells are located in the ventral part of the SCN, in apposition with the optic chiasm, making these cells the best candidates for receiving light input. VIP+ cells send projections to the entire SCN, affecting the functions of other VIP+ cells and clock cells located in the shell of the SCN (15). Here, we showed that in mice ipRGCs form direct synaptic connections with VIP cells, but also with somas of AVP and GRP neurons.…”

Section: Discussionmentioning

confidence: 71%

“…The SCN is a small nucleus located in the anterior hypothalamus and contains diverse subpopulations of neurons (13). Studies in rodents indicate that the core region located in the ventral portion of the SCN is composed of neurons that express vasoactive intestinal polypeptide (VIP) or gastrin-releasing peptide (GRP) (14,15). This core region is surrounded by a shell region that contains neurons expressing arginine vasopressin (AVP) and calretinin (16).…”

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confidence: 99%

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Architecture of retinal projections to the central circadian pacemaker

Fernandez

Chang

Hattar

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

137

134

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The suprachiasmatic nucleus (SCN) receives direct retinal input from the intrinsically photosensitive retinal ganglion cells (ipRGCs) for circadian photoentrainment. Interestingly, the SCN is the only brain region that receives equal inputs from the left and right eyes. Despite morphological assessments showing that axonal fibers originating from ipRGCs cover the entire SCN, physiological evidence suggests that only vasoactive intestinal polypeptide (VIP)/ gastrin-releasing peptide (GRP) cells located ventrally in the SCN receive retinal input. It is still unclear, therefore, which subpopulation of SCN neurons receives synaptic input from the retina and how the SCN receives equal inputs from both eyes. Here, using single ipRGC axonal tracing and a confocal microscopic analysis in mice, we show that ipRGCs have elaborate innervation patterns throughout the entire SCN. Unlike conventional retinal ganglion cells (RGCs) that innervate visual targets either ipsilaterally or contralaterally, a single ipRGC can bilaterally innervate the SCN. ipRGCs form synaptic contacts with major peptidergic cells of the SCN, including VIP, GRP, and arginine vasopressin (AVP) neurons, with each ipRGC innervating specific subdomains of the SCN. Furthermore, a single SCNprojecting ipRGC can send collateral inputs to many other brain regions. However, the size and complexity of the axonal arborizations in non-SCN regions are less elaborate than those in the SCN. Our results provide a better understanding of how retinal neurons connect to the central circadian pacemaker to synchronize endogenous circadian clocks with the solar day.melanopsin | circadian | suprachiasmatic nucleus | non-image-forming functions | ipRGCs T he suprachiasmatic nucleus (SCN) houses a central pacemaker that orchestrates circadian (circa: "about" and diem: "day") behaviors that cycle with a period close to 24 h. This endogenous clock is self-sustained even in the complete absence of external stimuli, but can be entrained to the light/dark cycle of the solar day in a process defined as circadian photoentrainment (1). In mammals, phototransduction solely occurs in the retina (2). Retinal ganglion cells (RGCs) are projection neurons of the retina that send light information to brain targets (3). Although the majority of RGCs project to brain areas involved in object tracking and image formation, some RGCs also innervate non-image-forming brain regions to influence circadian activity, sleep, the pupillary light response, mood, and learning functions (4).Recent studies showed that a small subpopulation of RGCs expresses a photopigment called melanopsin (Opn4), making these cells intrinsically photosensitive (ip)RGCs (5-7). It is now known that there are at least five different ipRGC subtypes (M1-M5) (8, 9). Using genetic tracing techniques, it was shown that ipRGCs send projections to non-image-forming centers in the brain, including the SCN, which receives retinal input predominantly from M1 ipRGCs (10-12) and to a lesser extent from M2 ipRGCs (12). The SCN is a smal...

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Section: Retinal Projections To the Scn: Identification Of Postsynaptsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 71%

mentioning

confidence: 99%

See 1 more Smart Citation

Architecture of retinal projections to the central circadian pacemaker

Fernandez

Chang

Hattar

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

137

134

View full text Add to dashboard Cite

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“…4 A). Consistent with the expression pattern of PACAP receptors (Kalamatianos et al, 2004), PACAP was also found to elicit pMSK1 expression in periventricular regions dorsal to the SCN. Discernable PACAPinduced pMSK1 expression was observed in 75% of the animals (n ϭ 8).…”

Section: Pacap-dependent Msk1 Activationsupporting

confidence: 73%

Light Stimulates MSK1 Activation in the Suprachiasmatic Nucleus via a PACAP-ERK/MAP Kinase-Dependent Mechanism

Butcher

Lee²,

Cheng³

et al. 2005

J. Neurosci.

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“…Studies have identified three candidate output signals, TGF-␣, cardiotrophin-like cytokine, and prokineticin 2, all of which inhibit locomotor activity (5,22,23). Vasoactive intestinal peptide (VIP) is a neurotransmitter expressed in many neuronal soma of the ventromedial SCN, which receives photic input from the retinohypothalamic tract (20). Processes from these neurons extend throughout the SCN as well as into the adjacent subparaventricular zone (SPZ).…”

mentioning

confidence: 99%

Chronic stimulation of the hypothalamic vasoactive intestinal peptide receptor lengthens circadian period in mice and hamsters

Pantazopoulos

Dolatshad

Davis

2010

American Journal of Physiology-Regulatory, Integrative and Comp

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) lack normal circadian activity, probably because of loss of synchronization among SCN neurons and a loss of rhythmicity in individual cells (2,3,6,8,17,29). Moreover, SCN transplants that are successful in restoring rhythms express VIP (24, 34), suggesting that VIP is a possible SCN output signal.In addition to possible roles in coupling and output, VIP-VIP receptor (VPAC2) signaling may be involved in transduction of photic input to SCN cells. Studies have shown that VIP pulses result in phase delays or phase advances of locomotor activity, depending on circadian time of administration (32). These effects are similar to the phase-shifting effects of light pulses. Electrophysiological investigations have shown that application of VIP, or a VPAC2 receptor agonist, have similar phase-shifting effects on the firing rates of SCN neurons (36). VIP pulses have also been shown to induce expression of the clock genes per1 and per2 (30), similar to the effect of light pulses on per gene expression.Taken together, these findings indicate that VIP mediates several important aspects of circadian rhythm regulation by the SCN. Whereas mice lacking VPAC2 or VIP show either shorter periods or complete loss of rhythmic activity (2, 7), the effect of chronic VPAC2 receptor activation has not been examined. Based on the evidence of a role for VIP-VPAC2 signaling in integrating light information to SCN neurons, together with disruptions in wheelrunning activity and synchrony of SCN neurons in vip Ϫ/Ϫ mice, we hypothesized that chronic stimulation of the VPAC2 receptor may result in lengthening of the period, similar to the effect of constant light (9). In addition, chronic stimulation of the VPAC2 receptor could result in increased or decreased synchrony among SCN cells. If synchrony is decreased, activity rhythms could be disrupted similar to knockout mice. If synchrony is increased, it is expected that the amplitude of a rhythm expressed by a population of rhythmic cells will increase. For example, this might be seen as higher peak expression of a key circadian regulatory gene, per2. Because VIP processes extend outside the SCN, VIP might also act as an output signal from the SCN. If so, chronic stimulation of the VPAC2 receptor in regions adjacent to the SCN through intraventricular infusion should affect activity levels. To test these hypotheses, we chronically infused a potent VPAC2 receptor agonist 44)] in the third ventricle of Syrian hamsters while monitoring wheel-running activity. In addition, we examined the effect of chronic application of BAY 55-9837 on period and amplitude of PER2 expression measured by bioluminescence in cultured SCN explants.

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Expression of VIP and/or PACAP receptor mRNA in peptide synthesizing cells within the suprachiasmatic nucleus of the rat and in its efferent target sites

Cited by 62 publications

References 122 publications

Architecture of retinal projections to the central circadian pacemaker

Architecture of retinal projections to the central circadian pacemaker

Light Stimulates MSK1 Activation in the Suprachiasmatic Nucleus via a PACAP-ERK/MAP Kinase-Dependent Mechanism

Chronic stimulation of the hypothalamic vasoactive intestinal peptide receptor lengthens circadian period in mice and hamsters

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