The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Franziska Wollnik - One of the best experts on this subject based on the ideXlab platform.
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Involvement of the retinohypothalamic tract in the photic-like effects of the Serotonin Agonist quipazine in the rat.
Neuroscience, 2005Co-Authors: Carole Graff, Markus Kohler, Paul Pevet, Franziska WollnikAbstract:Light is the major synchronizer of the mammalian circadian pacemaker located in the suprachiasmatic nucleus. Photic information is perceived by the retina and conveyed to the suprachiasmatic nucleus either directly by the retinohypothalamic tract or indirectly by the intergeniculate leaflet and the geniculohypothalamic tract. In addition, Serotonin has been shown to affect the suprachiasmatic nucleus by both direct and indirect Serotonin projections from the raphe nuclei. Indeed, systemic as well as local administrations of the Serotonin Agonist quipazine in the region of the suprachiasmatic nucleus mimic the effects of light on the circadian system of rats, i.e. they induce phase-advances of the locomotor activity rhythm as well as c-FOS expression in the suprachiasmatic nucleus during late subjective night. The aim of this study was to localize the site(s) of action mediating those effects. Phase shifts of the locomotor activity rhythm as well as c-FOS expression in the suprachiasmatic nucleus after s.c. injection of quipazine (10 mg/kg) were assessed in Lewis rats, which had received either radio-frequency lesions of the intergeniculate leaflet or infusions of the Serotonin neurotoxin 5,7-dihydroxytryptamine into the suprachiasmatic nucleus (25 microg) or bilateral enucleation. Lesions of intergeniculate leaflet and Serotonin afferents to the suprachiasmatic nucleus did not reduce the photic-like effects of quipazine, whereas bilateral enucleation and the subsequent degeneration of the retinohypothalamic tract abolished both the phase-shifting and the FOS-inducing effects of quipazine. The results indicate that photic-like effects of quipazine are mediated via the retinohypothalamic tract.
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Local effects of the Serotonin Agonist quipazine on the suprachiasmatic nucleus of rats.
Neuroreport, 1999Co-Authors: Andreas Kalkowski, Franziska WollnikAbstract:In mammals, circadian rhythms of locomotor activity and many other behavioral and physiological functions are controlled by an endogenous pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). One of the SCN's afferents is a dense serotonergic input from the mesencephalic raphe complex. Previous work from this laboratory demonstrated that systemic administrations of the Serotonin Agonist quipazine mimic the effects of light on the circadian system of rats, i.e. they induce photic-like phase shifts of the circadian activity rhythm as well as c-Fos expression in the SCN. In contrast, no such effect has been demonstrated so far in the isolated rat SCN slice preparation. In this study we demonstrate that local injections of quipazine (0.5 microg/kg) into the region of the SCN induce photic-like effects similar to those induced by systemic injections. These findings suggest a role for 5-HT in the transmission of photic information to the rat circadian system through a direct action at the level of the SCN.
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Serotonin Agonist quipazine induces photic-like phase shifts of the circadian activity rhythm and c-Fos expression in the rat suprachiasmatic nucleus.
Journal of biological rhythms, 1999Co-Authors: Markus Kohler, Andreas Kalkowski, Franziska WollnikAbstract: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). Furthermore, they investigated the effect of quipazine on the expression of c-Fos in the mammalian circadian pacemaker, the suprachiasmatic nucleus (SCN). Quipazine reduced the amount of running wheel activity for 3 h after treatment, however, no long-term changes in τ and in the activity level were observed. More important, quipazine induced significant phase advances of the activity rhythm and c-Fos production in the SCN at the end of the subjective night (Circadian Time [CT] 22), whereas neither phase shifts nor c-Fos induction were observed during the subjective day. Quipazine injections also resulted in moderate phase delays at the beginning of the subjectiv...
Isabelle Vivodtzev - One of the best experts on this subject based on the ideXlab platform.
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Serotonin 1a Agonist and cardiopulmonary improvements with whole body exercise in acute high level spinal cord injury a retrospective analysis
European Journal of Applied Physiology, 2021Co-Authors: Isabelle Vivodtzev, Glen Picard, Kevin C Oconnor, Andrew J TaylorAbstract:PURPOSE High-level spinal cord injury (SCI) can result in spinal and supraspinal respiratory control deficits leading to insufficient ventilatory responses to exercise and training-related adaptations. We hypothesized a Serotonin Agonist, known to improve respiratory function in animal models, would improve adaptations to whole-body functional electrical stimulation (FES) exercise training in patients with acute high-level SCI. METHODS We identified 10 patients ( 0.66, p < 0.05). CONCLUSION These results suggest Buspirone improves cardiorespiratory adaptations to FES-exercise training in individuals with acute, high-level SCI. The strong association between increases in ventilatory and aerobic capacities suggests improved respiratory function is a mechanism; however, controlled studies are needed to determine if this preliminary finding is reproducible.
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Serotonin 1A Agonist and cardiopulmonary improvements with whole-body exercise in acute, high-level spinal cord injury: a retrospective analysis
European Journal of Applied Physiology, 2020Co-Authors: Isabelle Vivodtzev, Glen Picard, Kevin O’connor, J. Andrew TaylorAbstract:Purpose High-level spinal cord injury (SCI) can result in spinal and supraspinal respiratory control deficits leading to insufficient ventilatory responses to exercise and training-related adaptations. We hypothesized a Serotonin Agonist, known to improve respiratory function in animal models, would improve adaptations to whole-body functional electrical stimulation (FES) exercise training in patients with acute high-level SCI. Methods We identified 10 patients (
Andrew J Taylor - One of the best experts on this subject based on the ideXlab platform.
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Serotonin 1a Agonist and cardiopulmonary improvements with whole body exercise in acute high level spinal cord injury a retrospective analysis
European Journal of Applied Physiology, 2021Co-Authors: Isabelle Vivodtzev, Glen Picard, Kevin C Oconnor, Andrew J TaylorAbstract:PURPOSE High-level spinal cord injury (SCI) can result in spinal and supraspinal respiratory control deficits leading to insufficient ventilatory responses to exercise and training-related adaptations. We hypothesized a Serotonin Agonist, known to improve respiratory function in animal models, would improve adaptations to whole-body functional electrical stimulation (FES) exercise training in patients with acute high-level SCI. METHODS We identified 10 patients ( 0.66, p < 0.05). CONCLUSION These results suggest Buspirone improves cardiorespiratory adaptations to FES-exercise training in individuals with acute, high-level SCI. The strong association between increases in ventilatory and aerobic capacities suggests improved respiratory function is a mechanism; however, controlled studies are needed to determine if this preliminary finding is reproducible.
Cynthia L. Bethea - One of the best experts on this subject based on the ideXlab platform.
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Effect of cocaine injections on the neuroendocrine response to the Serotonin Agonist MK-212.
Biological psychiatry, 1992Co-Authors: Louis D. Van De Kar, Peter A. Rittenhouse, Patricia A. O'connor, Thomas Palionis, Mark S. Brownfield, Stephanie J. Lent, Molly Carnes, Cynthia L. BetheaAbstract:Abstract This study was undertaken to examine whether several of the hormones that can be released by activation of Serotonin receptors will be affected by long-term cocaine administration. Male rats received cocaine injections (15 mg/kg, IP) twice daily for 7 days. Forty-two hr after the last cocaine injection, the rats were challenged with increasing doses (0, 1, 5, 10 mg/kg, IP) of the 5-HT 1 /5-HT 2 Agonist MK-212 (6-chloro-2-[1-piperazinyll-pyrazine). The following observations were made: (1) cocaine reduced the rate of body weight gain; (2) cocaine inhibited the stimulatory effect of MK-212 on plasma vasopressin, oxytocin, and prolactin concentrations and on plasma renin activity and concentration; (3) cocaine did not inhibit the stimulatory effect of MK-212 on plasma ACTH or corticosterone concentrations. The data indicate that a wide-spectrum 5-HT (Serotonin) Agonist such as MK-212 can reveal differential neuroendocrine responses. This effect could be related to cocaine-induced changes in the different 5-HT receptor subtypes that regulate the secretion of these hormones.
Markus Kohler - One of the best experts on this subject based on the ideXlab platform.
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Involvement of the retinohypothalamic tract in the photic-like effects of the Serotonin Agonist quipazine in the rat.
Neuroscience, 2005Co-Authors: Carole Graff, Markus Kohler, Paul Pevet, Franziska WollnikAbstract:Light is the major synchronizer of the mammalian circadian pacemaker located in the suprachiasmatic nucleus. Photic information is perceived by the retina and conveyed to the suprachiasmatic nucleus either directly by the retinohypothalamic tract or indirectly by the intergeniculate leaflet and the geniculohypothalamic tract. In addition, Serotonin has been shown to affect the suprachiasmatic nucleus by both direct and indirect Serotonin projections from the raphe nuclei. Indeed, systemic as well as local administrations of the Serotonin Agonist quipazine in the region of the suprachiasmatic nucleus mimic the effects of light on the circadian system of rats, i.e. they induce phase-advances of the locomotor activity rhythm as well as c-FOS expression in the suprachiasmatic nucleus during late subjective night. The aim of this study was to localize the site(s) of action mediating those effects. Phase shifts of the locomotor activity rhythm as well as c-FOS expression in the suprachiasmatic nucleus after s.c. injection of quipazine (10 mg/kg) were assessed in Lewis rats, which had received either radio-frequency lesions of the intergeniculate leaflet or infusions of the Serotonin neurotoxin 5,7-dihydroxytryptamine into the suprachiasmatic nucleus (25 microg) or bilateral enucleation. Lesions of intergeniculate leaflet and Serotonin afferents to the suprachiasmatic nucleus did not reduce the photic-like effects of quipazine, whereas bilateral enucleation and the subsequent degeneration of the retinohypothalamic tract abolished both the phase-shifting and the FOS-inducing effects of quipazine. The results indicate that photic-like effects of quipazine are mediated via the retinohypothalamic tract.
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Serotonin Agonist quipazine induces photic-like phase shifts of the circadian activity rhythm and c-Fos expression in the rat suprachiasmatic nucleus.
Journal of biological rhythms, 1999Co-Authors: Markus Kohler, Andreas Kalkowski, Franziska WollnikAbstract: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). Furthermore, they investigated the effect of quipazine on the expression of c-Fos in the mammalian circadian pacemaker, the suprachiasmatic nucleus (SCN). Quipazine reduced the amount of running wheel activity for 3 h after treatment, however, no long-term changes in τ and in the activity level were observed. More important, quipazine induced significant phase advances of the activity rhythm and c-Fos production in the SCN at the end of the subjective night (Circadian Time [CT] 22), whereas neither phase shifts nor c-Fos induction were observed during the subjective day. Quipazine injections also resulted in moderate phase delays at the beginning of the subjectiv...
