4 edition of Serotonin and nonphotic phase shifts found in the catalog.
Serotonin and nonphotic phase shifts
Matthew Howland Godfrey
Thesis (M.Sc.)--University of Toronto, 1993.
|Series||Canadian theses = Thèses canadiennes|
|The Physical Object|
|Pagination||2 microfiches : negative.|
The neurotransmitters neuropeptide Y and serotonin (5-HT) induce phase shifts very similar to a nonphotic stimulus when applied in vitro or in vivo. Furthermore, 5-HT release peaks at the onset of locomotor activity and increases transiently during periods of sleep deprivation. In Syrian hamsters, nonphotic stimuli, in the form of behavioral manipulations (e.g., social interaction, cage changing, novel wheel exposure, or sleep deprivation) or pharmacological intervention (e.g., 5-HT agonists or benzodiazepines) can induce phase shifts similar in magnitude to photic shifts .
derlie these nonphotic phase shifts. Some evidence suggests that serotonin from the raphe nuclei may underlie this effect (10), although this conclusion has been questioned (11). Neuropeptide Y from the intergeniculate leaflet appears to be both necessary (12) and sufficient (13) for nonphotic phase . Serotonin (5-HT) has been implicated in the phase adjustment of the circadian system during the subjective day in response to nonphotic stimuli. Two components of the circadian system, the suprachiasmatic nucleus (SCN) (site of the circadian clock) and the intergeniculate leaflet (IGL), receive serotonergic projections from the median raphe.
Bobrzynska KJ, Vrang N, Mrosovsky N () Persistence of nonphotic phase shifts in hamsters after serotonin depletion in the suprachiasmatic nucleus. Brain Res . Prosser RA. Melatonin inhibits in vitro serotonergic phase shifts of the suprachiasmatic circadian clock. Brain Res. ; – doi: /S(98) [Google Scholar] Prosser RA. Serotonin phase-shifts the mouse suprachiasmatic circadian clock in vitro.
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Nonphotic stimuli can reset and entrain circadian activity rhythms in hamsters and mice, and serotonin is thought to be involved in the phase-resetting effects of these stimuli.
In the present study, the authors examined the effect of the serotonin agonist quipazine on circadian activity rhythms in three inbred strains of rats (ACI, BH, and LEW).Cited by: SEROTONIN AND NONPHOTIC PHASE-SHIFTING EXPERIMENT 1 EFFECTS OF ACTIVITY RESTRICTION ON THE PHASE-SHIFTING EFFECTS OF 8-OH-DPAT IN AN ASCHOFF TYPE II EXPERIMENTAL DESIGN The purpose of this experiment was to look for a possible mediating role of activity, or a correlate, in the phase shifts produced by by: Moreover, higher doses of 8-OH-DPAT diminished activity on the day of injection but did not affect the amplitude of phase shifts.
Surprisingly, quipazine (a non specific 5-HT agonist), when injected in the middle of subjective day did not phase shift the activity rhythm of hamsters, as it Cited by: A nonphotic action of cocaine was apparent from its induction of 1-h circadian phase-advance shifts at midday.
The serotonin receptor antagonist, metergoline, blocked shifting by 80%, implicating. Such shifts can be as great in magnitude as light-induced phase shifts. The term, non-photic stimulus, has had a non-specific use in reference to any non-light input to the circadian clock, including such endogenous neurotransmitters as serotonin agonists that are internally administered to test animals.
Serotonin agonists (quipazine and 8-OH-DPAT) have phase-shifting effects on the circadian rhythm of firing rate of rat SCN cells consistent with a role in nonphotic phase-shifts [19,35,36,40]. In vivo (systemic and intraventricular) ad- ministration of quipazine in rats and 8-OH-DPAT in ham- sters produce phase advances when given in the.
Serotonin is the raphe neurotransmitter that triggers phase shifts, inhibits light-induced phase-shifts, and plays a role in controlling the sleep-wake cycle. 5-HT has been shown to play a. These phase shifts were completely blocked by the 5-HT antagonist, metergoline.
DPAT also induced phase shifts when applied during mid-subjective day, and this effect appeared dose-dependent. Together, these results demonstrate that the mouse SCN, like that of the rat, is directly sensitive to in vitro phase-resetting by 5-HT.
This volume contains the proceedings of the Ninth Meeting of the "International Study Group for Tryptophan Research" (lSTRY), held at the University of Hamburg, Germany, from October 10 to 14, At this meeting the recent developments in the field of tryptophan research were presented by leading researchers from all over the world in 81 oral and 48 poster contri butions.3/5(2).
In France, Serotonin was the best-selling fiction book in the week it was released. Within three days of its publication, it had s copies.  The release was considered a national event, coming as it did the same month Houellebecq was awarded the Legion of Honour.
Also, 5HTergic agonists can modulate shifts to light pulses, and under certain conditions, can induce nonphotic type phase shifts Knoch et al., ; Morin and Allen, ).
Although most. Serotonergic mediation of constant light-potentiated nonphotic phase shifting of the circadian locomotor activity rhythm in Syrian hamsters. Knoch ME(1), Siegel D, Duncan MJ, Glass JD. Author information: (1)Department of Biological Sciences, Kent State University, Kent, OHby: These findings suggest that the 5-HT(1A) receptor plays an inhibitory role in behavioral phase shifts, a facilitatory role in light-induced gene expression, a necessary role in phase shifts to 8-OH-DPAT, and is not necessary for activity-induced phase advances that oppose photic phase shifts to long light pulses.
This volume contains the proceedings of the Ninth Meeting of the "International Study Group for Tryptophan Research" (lSTRY), held at the University of Hamburg, Germany, from October 10 to 14, At this meeting the recent developments in the field of tryptophan research were presented by.
The SCN serotonin release associated with arousal-induced phase-shifts is blocked by intra-dorsal raphe injections of 5-HT 1,2,7 and 5-HT 7 antagonist, indicating the role of dorsal raphe output. In the mammalian circadian system, serotonin is involved in photic as well as nonphotic regulation of circadian rhythms, but its role in this is still controversial.
In our previous experiments we characterized the phase response curve for (R)-(+)OH-DPAT under constant light (LL) in mice, and found its shape to resemble the PRC for dark. Brief (~2 day) constant light exposure (LL b) in hamsters dramatically enhances circadian phase-resetting induced by the serotonin (5-HT) receptor agonist, 8-OH-DPAT and other nonphotic present study was undertaken to determine if LL b can also amplify phase-resetting responses to endogenous 5-HT and accelerate re-entrainment to large-magnitude advance and delay shifts.
For example, 5-HT agonists are capable of phase shifting the biological clock both in vivo and in vitro, producing phase response curves (PRCs) similar in shape to those of other nonphotic stimuli. Therefore we studied the role of the serotonergic projection to the SCN in nonphotic phase shifts by bilateral injection of the selective 5-HT Cited by: Antle MC, Marchant EG, Niel L, Mistlberger RE.
Serotonin antagonists do not attenuate activity-induced phase shifts of circadian rhythms in the Syrian hamster. Brain Research,Mistlberger RE, Bossert JM, Holmes MM, Marchant EG. Serotonin and feedback effects of behavioral activity on circadian rhythms in mice.
Serotonin, a putative neurotransmitter in insects, was found to cause consistent phase shifts of the circadian rhythm of locomotor activity of the cockroach Leucophaea maderae when administered during the early subjective night as a series of 4-μl pulses (one every 15 min) for either 3 or 6 hr.
Six-hour treatments with dopamine also caused significant phase shifts during the early subjective. Also, phase-advance shifts induced by novel wheel access at midday were suppressed, but not blocked, by intra-DRN injection of DR or muscimol.
These results indicate that 5-HT7 and GABAergic receptors of the DRN and MRN regulate behaviorally induced 5-HT release in the SCN, and that DRN output modulates nonphotic phase-resetting responses.Serotonin (5-HT) is thought to play a role in regulating nonphotic phase shifts and modulating photic phase shifts of the mammalian circadian system, but results with different species (rats vs.
hamsters) and techniques (in vivo vs. in vitro; systemic vs. intracerebral drug delivery) have been discordant.CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Circadian or daily rhythms generated from the mammalian suprachiasmatic nuclei (SCN) of the hypothalamus can be syn-chronized by light and nonphotic stimuli.
Whereas glutamate mediates photic information, nonphotic information can in some cases be mediated by neuropeptide Y (NPY) or serotonin.