Daily variations of various parameters of serotonin metabolism in the rat brain. I. Circadian variations of tryptophan-5-hydroxylase in the raphe nuclei and the striatum

Kan, Jean-Paul; Chouvet, Guy; Héry, F.; Debilly, G.; Mermet, A.; Głowiński, J.; Pujol, Jean‐François

doi:10.1016/0006-8993(77)90647-3

Cited by 60 publications

(13 citation statements)

References 17 publications

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“…The serotonergic neurons show marked circadian rhythms in firing rate [19,25], regional brain levels [14,[31][32][33] and synthesis rate [17,20]. The action of 5-HT on the firing of SCN neurons has been shown to be inhibitory [10], The site at which the serotonergic fibers develop their rhythmicity may be the hippocampus.…”

Section: Variation Of Corticosterone Levelsmentioning

confidence: 99%

Effects of Microinjections of 5,7-Dihydroxytryptamine in the Suprachiasmatic Nuclei of the Rat on Serotonin Reuptake and the Circadian Variation of Corticosterone Levels

et al. 1983

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The role of the 5-hydroxytryptamine (5-HT) terminals in the suprachiasmatic nucleus (SCN) in the production of the circadian variation of corticosterone secretion was investigated by lesioning the 5-HT inputs to the SCN with 5,7-di-hydroxytryptamine (5,7-DHT). Vehicle-injected animals showed a normal circadian variation of corticosterone levels. In contrast, the mean corticosterone levels of the 5,7-DHT-lesioned group were intermediate between control peak and trough values, and although the individual rats showed fluctuations, no significant circadian variation was present in the group as a whole. ³H-5-HT reuptake in the SCN was reduced to 38% of the mean control level in the 5,7-DHT-lesioned group, but ventromedial hypothalamic ³H-5-HT reuptake was only decreased to 82% of control. These results indicated that the SCN 5-HT terminals may play an important role in the synchronization of the circadian variation of corticosterone secretion.

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Section: Variation Of Corticosterone Levelsmentioning

confidence: 99%

Effects of Microinjections of 5,7-Dihydroxytryptamine in the Suprachiasmatic Nuclei of the Rat on Serotonin Reuptake and the Circadian Variation of Corticosterone Levels

et al. 1983

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“…Daily variations of tryptophan hydroxylase (TrpHase) in the raphe nuclei were demonstrated by Kan et al (27). Tryptophan hydroxylase rhythms in the RD and the RM exhibit daily fluctuation with an almost identical acrophase at the end of the dark period.…”

Section: Discussionmentioning

confidence: 95%

Twenty-Four Hour Rhythms of Norepinephrine and Serotonin in Nucleus Suprachiasmaticus, Raphe Nuclei, and Locus Coeruleus in the Rat

Semba

Toru

Mataga

1984

Sleep

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Summary: Twenty-four hour rhythms, at 4 h intervals, of norepinephrine (NE) and serotonin (5-HT) contents were investigated in the rat brain regions where sleep-wakefulness regulation is believed to occur: Nucleus suprachiasmaticus (SC), n, raphe dorsalis (RD) and medialis (RM), and locus coeruleus, Cosinor method of Halberg was applied to evaluate sinusoidal rhythmicity of the measured values, In the SC only NE showed a significant rhythm with a peak value at the beginning of the light period, which suggests that a NE mechanism may be involved in oscillating biological rhythms in rats, In the RD and RM, 5-HT and 5-hydroxyindoleacetic acid increased significantly during the light period, Moreover, 5-HT rhythm in the RD was maintained even under constant dark conditions, which suggests that 5-HT rhythm in the RD may be endogenous, Key Words: Twentyfour hour rhythm-Norepinephrine-Serotonin-Nucleus suprachiasmaticusRaphe nuclei-Locus coeruleus, Most physiological functions in rodents, such as locomotion, feeding and drinking, thermoregulation, and hormonal secretion, exhibit circadian rhythms. These rhythms are believed to be controlled by a pacemaker located in the nucleus suprachiasmaticus (SC) of the hypothalamus (1). Physiological rhythms may be affected by biochemical changes in the brain. It has been demonstrated that norepinephrine (NE) and serotonin (5-HT) contents in the whole brain or some brain regions change over a 24 h period (2-6). Recently Ibuka et al. (7) found that the sleep-wakefulness cycle is also regulated by the circadian pacemaker in the SC. Although Jouvet has recently modified his monoamine hypothesis of sleep and stressed the importance of the cholinergic mechanisms (8,9), studying the interactions between 5-HT and NE in sleep-wakefulness regulation is still useful.We have studied the 24 h changes in 5-HT and NE contents in the n. raphe dorsalis (RD) and medialis (RM), locus coeruleus (LC), and SC in the rat. To investigate whether a 24 h rhythm in the raphe nuclei is endogenous, an additional experiment was carried out.

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“…On the other hand, the total protein content can fluctuate unspecifically in physiological conditions, e.g. in response to circadian rhythms (Kan et al 1977) or chronic hypoxia (Poncet, Denoroy, Dalmaz, Pequignot & Jouvet, 1995). Accordingly, expression of catecholamine activity per structure is more appropriate than the expression of results per milligram protein, in order to avoid artefactual variations in the catecholamine content and turnover following modifications of total protein levels in the structure.…”

Section: Animalsmentioning

confidence: 99%

Long‐term influence of neonatal hypoxia on catecholamine activity in carotid bodies and brainstem cell groups of the rat.

Soulier

Dalmaz

Cottet-Émard

et al. 1997

The Journal of Physiology

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1. In order to determine the long-term influence of neonatal hypoxia on catecholaminergic activity in peripheral arterial chemoreceptors and brainstem noradrenergic cell groups (Al, A2, A5 and A6), 1-day-old male rat pups were subjected to hypoxia (10% oxygen) for 6 days and then supplied with normal air. Control animals were kept at normoxia from birth. Rats were killed at either 3 or 8 weeks of age. 2. The content of dopamine and noradrenaline in carotid bodies of neonatally hypoxic rats was increased at both 3 and 8 weeks of age. 3. Noradrenaline turnover was selectively decreased in the caudal portion of A2 (located in the area of chemosensory afferent projection) at 8 weeks of age (-76 + 2 %), while this turnover was unaffected in rostral A2 cells. Noradrenergic activity in Al, A5 and A6 was altered by neonatal hypoxia in an age-dependent fashion. 4. The data suggest that neonatal hypoxia induces long-term changes in the basal activity of the carotid body and brainstem noradrenergic cell groups. Such changes might contribute to neuronal regulation of the delayed respiratory, arousal and neural sequelae associated with neonatal hypoxia. These changes could also be involved in the early programming of respiratory and blood pressure control.

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Daily variations of various parameters of serotonin metabolism in the rat brain. I. Circadian variations of tryptophan-5-hydroxylase in the raphe nuclei and the striatum

Cited by 60 publications

References 17 publications

Effects of Microinjections of 5,7-Dihydroxytryptamine in the Suprachiasmatic Nuclei of the Rat on Serotonin Reuptake and the Circadian Variation of Corticosterone Levels

Effects of Microinjections of 5,7-Dihydroxytryptamine in the Suprachiasmatic Nuclei of the Rat on Serotonin Reuptake and the Circadian Variation of Corticosterone Levels

Twenty-Four Hour Rhythms of Norepinephrine and Serotonin in Nucleus Suprachiasmaticus, Raphe Nuclei, and Locus Coeruleus in the Rat

Long‐term influence of neonatal hypoxia on catecholamine activity in carotid bodies and brainstem cell groups of the rat.

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