Circadian rhythm of neuronal activity in suprachiasmatic nucleus slices from the vasopressin-deficient Brattleboro rat

Ingram, C.D.; Snowball, R.K; Mihai, Radu

doi:10.1016/0306-4522(96)00274-6

Cited by 50 publications

(34 citation statements)

References 31 publications

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“…In addition to the possible output function of AVP production on the SCN, there may also be an internal function. SCN neurons in acute brain slices from Brattleboro rats increase their ®ring rate when treated with AVP (Ingram et al 1996). Hence, AVP content in the SCN after post-hibernation arrhythmicity might be indicative of regaining function by the SCN.…”

Section: Re-entrainment Hypothesismentioning

confidence: 99%

“…AVP neurons form soma-somatic appositions and have extensive synaptic relationships with other (AVP) neurons in both ipsilateral and contralateral SCN, indicating a mechanism for strong intercellular coupling (Van den Pol and Gorcs 1986;Castel et al 1990). AVP-induced excitation within the SCN in combination with this elaborated intrinsic SCN connectivity has been postulated to determine the power of circadian rhythms (Ingram et al 1996). Therefore, the increase of AVP immunoreactivity in the SCN during the ®rst 2 weeks after the end of hibernation suggests a gradual increase of AVP activity, resulting in an increase in the amplitude of the AVP output signal as well as enhancement of synchronisation between SCN cells.…”

Section: Correlations With Numbers Of Avpir Neurons In the Scnmentioning

confidence: 99%

“…AVP is present in SCN cells of ground squirrels (Reuss et al 1989;Schindler and NuÈ rnberger 1990;Smale et al 1991) and has been implicated as a key neuropeptide in the control of the circadian pacemaker in the mammalian SCN over behavioural rhythms in mice (Bult et al 1993), rats (Wollnik and Bihler 1996), and voles (Gerkema et al 1994;Jansen et al 1999). Brattleboro rats, lacking AVP production, remain circadian rhythmic, but circadian rhythmicity is more pronounced in heterozygotes as compared to homozygotes (Ingram et al 1996). This indicates that the SCN probably signals its circadian rhythmicity by more than one mechanism, and that AVP is a good candidate for one of these output signals from the mammalian circadian pacemaker.…”

Section: Re-entrainment Hypothesismentioning

confidence: 99%

“…AVP is considered to be a major output system of the SCN targeting other brain regions, synaptically and non-synaptically. In addition, Ingram et al (1996) concluded that AVP may amplify the circadian rhythm of SCN neurons via the V1 receptor pathway. Correlations of AVP with expression of circadian rhythms have been found most clearly in spontaneously arrhythmic common voles.…”

Section: Correlations With Numbers Of Avpir Neurons In the Scnmentioning

confidence: 99%

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Gradual reappearance of post-hibernation circadian rhythmicity correlates with numbers of vasopressin-containing neurons in the suprachiasmatic nuclei of European ground squirrels

Hut

Zee

Jansen

et al. 2002

Journal of Comparative Physiology B: Biochemical, Systemic, and

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Gradual reappearance of post-hibernation circadian rhythmicity correlates with numbers of vasopressin-containing neurons in the suprachiasmatic nuclei of European ground squirrels Hut, R.A; van der Zee, E.A; Jansen, K; Gerkema, M.P.; Daan, S. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract European ground squirrels (Spermophilus citellus) in outside enclosures show suppressed circadian rhythmicity in body temperature patterns during the ®rst days of euthermia after hibernation. This may re¯ect either gradual reappearance of circadian rhythmicity following suppressed functioning of the circadian system during hibernation, or it may re¯ect transient days during re-entrainment of the circadian system which, during hibernation, has drifted out of phase with the environmental light-dark cycle. Here we report that animals kept under continuous dim light conditions also showed absence of circadian rhythmicity in activity and body temperature in the ®rst 5±15 days after hibernation. After post-hibernation arrhythmicity, spontaneous circadian rhythms re-appeared gradually and increased daily body temperature range. Numbers of argininevasopressin immunoreactive neurons in the suprachiasmatic nuclei correlated positively with individual circadian rhythmicity and increased gradually over time after hibernation. Furthermore, circadian rhythmicity was enhanced rather than suppressed after exposure to a light-dark cycle but not after a single 1-h light pulse (1,700 lux). The results support the view that the functioning of the circadian system in the European ground squirrel is suppressed during hibernation at low temperatures and that it requires several days of euthermia to resume its summer function.Keywords Hibernation á Post-hibernation arrhythmicity á Circadian system á SCN á AVP Abbreviations AVP arginine-vasopressin á AVPir AVPimmunoreactive á ct circadian time á LD light-dark á PAF paraformaldehyde á PB phosphate buer á PBS phosphate-buered saline á SCN suprachiasmatic nuclei á SON supraoptic nuclei

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Section: Re-entrainment Hypothesismentioning

confidence: 99%

Section: Correlations With Numbers Of Avpir Neurons In the Scnmentioning

confidence: 99%

Section: Re-entrainment Hypothesismentioning

confidence: 99%

Section: Correlations With Numbers Of Avpir Neurons In the Scnmentioning

confidence: 99%

See 2 more Smart Citations

Gradual reappearance of post-hibernation circadian rhythmicity correlates with numbers of vasopressin-containing neurons in the suprachiasmatic nuclei of European ground squirrels

Hut

Zee

Jansen

et al. 2002

Journal of Comparative Physiology B: Biochemical, Systemic, and

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“…It is possible that there is direct transcriptional regulation of ion channel proteins or regulatory factors affecting channel activity by CLOCK/BMAL1. Clock genes may also regulate electrical activity indirectly via clock controlled genes (CCGs), such as vasopressin, which appears to augment the magnitude of the electrical activity rhythm in the SCN through a receptor-mediated excitation of SCN neurons [23,24].…”

Section: Circadian Clocks Exist In the Central Nerve System And In Thmentioning

confidence: 99%

What Role do Circadian Rhythms Play in Learning and Memory?

Mou¹

2016

J Neurol Neurophysiol

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Circadian rhythmicity in gene expression and physiological process has been observed both in the central nervous system and in the periphery, including the hippocampus. As a center for memory formation and storage, the hippocampus shows circadian rhythmicity in clock gene expression and synaptic plasticity. Circadian variation in performance of hippocampus-dependent memory task suggests a link between clock gene oscillation and behavioral response. Yet the discrepancy in time scale between fast information encoding during memory acquisition and much slower circadian oscillation in cellular processes casts doubt on the underlying mechanism of circadian regulation of learning and memory. This short review suggests that instead of being a modulator of learning process and memory formation, the time-of-day information itself could be integrated as a component of episodic memory for later consolidation and retrieval.

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The role ofClock in the developmental expression of neuropeptides in the suprachiasmatic nucleus

et al. 2000

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The suprachiasmatic nucleus (SCN) is the dominant circadian pacemaker in mammals. To understand better the ontogeny of mouse SCN and the role of the pacemaker in peptide expression, the authors examined the distribution of cells that were immunoreactive for vasopressin (AVP) or vasoactive intestinal polypeptide (VIP) in wild type and Clock mutant mice at two developmental stages. Clock homozygous mice failed to show the dramatic increase in the number of VIP-immunoreactive (VIP-ir) neurons from postnatal day 6 (P6) to P30 that was found in the SCN of wild type mice. The number of AVP-ir neurons was relatively constant in the postnatal SCN but was significantly reduced in Clock/Clock mice. The effects of the Clock mutation varied with position in the SCN for both peptides. Densitometry of immunolabeled brains indicated that the Clock mutation reduced AVP expression specifically in the SCN and not in other brain areas. The SCN did not significantly change shape or size with age or Clock genotype. Taken together, these results indicate that the neonatal mouse SCN has its full complement of cells, some of which are not yet mature in their neuropeptide content. Furthermore, the observation that the Clock mutation appears to act on a subset of AVP and VIP cells suggests heterogeneity within these cell classes in the SCN.

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Circadian rhythm of neuronal activity in suprachiasmatic nucleus slices from the vasopressin-deficient Brattleboro rat

Cited by 50 publications

References 31 publications

Gradual reappearance of post-hibernation circadian rhythmicity correlates with numbers of vasopressin-containing neurons in the suprachiasmatic nuclei of European ground squirrels

Gradual reappearance of post-hibernation circadian rhythmicity correlates with numbers of vasopressin-containing neurons in the suprachiasmatic nuclei of European ground squirrels

What Role do Circadian Rhythms Play in Learning and Memory?

The role ofClock in the developmental expression of neuropeptides in the suprachiasmatic nucleus

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