5-hydroxytryptophan, but not l-tryptophan, alters sleep and brain temperature in rats

Imeri, Luca; Mancia, M; Bianchi, Susanna; Opp, Mark R.

doi:10.1016/s0306-4522(99)00435-2

Cited by 46 publications

(34 citation statements)

References 31 publications

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“…Experiment 1: effects of 5-HTP administration on sleep-wake behavior and Tcort) was conducted at the University of Milan (by L. Imeri and S. Bianchi) to facilitate comparison with data derived from previous studies of the impact of 5-HTP on sleep-wake behavior of rats. These studies were conducted on the same strain of rats and under the same conditions previously reported (20). Experiment 2 (see Experimental Protocols.…”

Section: Methodsmentioning

confidence: 99%

“…Four doses of 5-HTP were tested: 25 (n ϭ 7), 50 (n ϭ 7), 75 (n ϭ 6), and 100 mg/kg (n ϭ 5). These are the same doses we used in our previous study (20) to determine the impact on sleep of rats of 5-HTP injected at dark onset. Experimental manipulations were randomly scheduled with an interval of at least 3 days between injections, and no animal received more than one vehicle and three doses of 5-HTP.…”

Section: Experimental Protocolsmentioning

confidence: 99%

“…Recent data directly support this dual role for 5-HT in regulation of the arousal state. We showed that increasing serotonergic activity at the beginning of the dark period by intraperitoneal injection of the 5-HT precursor L-5-hydroxytryptophan (5-HTP) results in dose-related and biphasic changes in sleep-wake behavior of rats; low doses initially enhance wakefulness, which is later followed by increased nonrapid eye movement (NREM) sleep (20). Under those experimental conditions, serotonergic activation at dark onset induces hypothermia, the duration of which encompasses periods of both increased wakefulness and enhanced NREM sleep.…”

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confidence: 99%

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Antagonism of corticotropin-releasing hormone alters serotonergic-induced changes in brain temperature, but not sleep, of rats

Imeri

Bianchi

Opp³

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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-Serotonin is involved in many physiological processes, including the regulation of sleep and body temperature. Administration into rats of low doses (25, 50 mg/kg) of the 5-HT precursor L-5-hydroxytryptophan (5-HTP) at the beginning of the dark period of the 12:12-h light-dark cycle initially increases wakefulness. Higher doses (75, 100 mg/kg) increase nonrapid eye movement (NREM) sleep. The initial enhancement of wakefulness after low-dose 5-HTP administration may be a direct action of 5-HT in brain or due to 5-HT-induced activation of other arousal-promoting systems. One candidate arousal-promoting system is corticotropin-releasing hormone (CRH) and the hypothalamicpituitary-adrenal axis. Serotonergic activation by 5-HTP at the beginning of the dark period also induces hypothermia. Because sleep and body temperature are influenced by circadian factors, one aim of this study was to determine responses to 5-HTP when administered at a different circadian time, the beginning of the light period. Results obtained show that all doses of 5-HTP (25-100 mg/kg) administered at light onset initially increase wakefulness; NREM sleep increases only after a long delay, during the subsequent dark period. Serotonergic activation by 5-HTP at light onset induces hypothermia, the time course of which is biphasic after higher doses (75, 100 mg/kg). Intracerebroventricular pretreatment with the CRH receptor antagonist ␣-helical CRH does not alter the impact of 5-HTP on sleep-wake behavior but potentiates the hypothermic response to 50 mg/kg 5-HTP. These data suggest that serotonergic activation by peripheral administration of 5-HTP may modulate sleep-wake behavior by mechanisms in addition to direct actions in brain and that circadian systems are important determinants of the impact of serotonergic activation on sleep and body temperature. thermoregulation; hypothermia; hypothalamic-pituitary-adrenal axis; corticotropin-releasing factor; 5-hydroxytryptamine EXTENSIVE EXPERIMENTAL DATA and clinical observations indicate that brain serotonin (5-HT) plays a pivotal role in the regulation of many physiological processes and complex behaviors (23), including sleep (25, 35) and thermoregulation (29,30). It is now thought that 5-HT, release of which is maximal during wakefulness, promotes wakefulness per se by actions on 5-HT 2 receptors and subsequently triggers sleep via induction of sleep-promoting systems (25,26). Recent data directly support this dual role for 5-HT in regulation of the arousal state. We showed that increasing serotonergic activity at the beginning of the dark period by intraperitoneal injection of the 5-HT precursor L-5-hydroxytryptophan (5-HTP) results in dose-related and biphasic changes in sleep-wake behavior of rats; low doses initially enhance wakefulness, which is later followed by increased nonrapid eye movement (NREM) sleep (20). Under those experimental conditions, serotonergic activation at dark onset induces hypothermia, the duration of which encompasses periods of both increased wakefulness and enhanced...

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Section: Methodsmentioning

confidence: 99%

Section: Experimental Protocolsmentioning

confidence: 99%

mentioning

confidence: 99%

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Antagonism of corticotropin-releasing hormone alters serotonergic-induced changes in brain temperature, but not sleep, of rats

Imeri

Bianchi

Opp³

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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“…In addition, both spontaneous and electrically evoked serotonin release from hypothalamic slices have been shown to be dependent on precursor availability, which causes parallel changes in brain serotonin levels and serotonin release (Schaechter & Wurtman, 1990). Central serotonin activity can affect many physiological responses, such as pain tolerance (Prieto-Gomez et al, 1989), motor activity (Gerin & Privat, 1998), thermoregulation (Imeri et al, 2000;Lin et al, 1998;Myers, 1981, Soares et al, 2007 and hypothalamo-pituitaryadrenal axis activity (Chaouloff, 2000;Korte et al, 1991). Thus, alterations in one or more of the physiological responses mediated by the serotonergic system may decrease work capacity during exercise.…”

Section: Central Fatigue Hypothesismentioning

confidence: 99%

The Involvement of Brain Monoamines in the Onset of Hyperthermic Central Fatigue

Coimbra¹,

Soares²,

Leite³

2012

An International Perspective on Topics in Sports Medicine and Sports Injury

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“…Fluctuations in the normal serotonin level are associated with a number of diseases. While low levels of 5-HT can cause depression, anxiety and migraines, high levels can result in toxicity and in extreme cases fatal effects such as serotonin syndrome, obsessive compulsive disorder, and autism [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

MWCNT-Chitosan-ZrO2 Nanocomposite Modified Sensor for Sensitive and Selective Electrochemical Determination of Serotonin

Devnani¹

2015

IJIRSET

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ABSTRACT:A novel sensitive electrochemical sensor has been developed by modification of glassy carbon electrode (GCE) with multi-walled carbon nanotube (MWCNT), chitosan (CHIT) and zirconium oxide (ZrO 2 ) nanoparticles. The morphological characteristics of nanocomposite (MWCNT-CHIT-ZrO 2 or MCZ) were studied by scanning electron microscope and atomic force microscopy. The electrochemical behavior of serotonin at nanocomposite modified GCE (MCZ/GCE) was investigated in pH 6.5 Briton Robinson buffer solution using cyclic voltammetry and square wave voltammetry. MCZ/GCE showed an enhancement in the current response as compared to bare GCE and showed a linear response to serotonin in the range 800 to 5000 nM. The limit of detection was found to be 0.6 nM, which is lower than many other sensors reported for serotonin in literature. The modified sensor showed high sensitivity (9 nA/nM) and selectivity for serotonin. The proposed method was successfully employed for quantification of serotonin in human blood serum samples.

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5-hydroxytryptophan, but not l-tryptophan, alters sleep and brain temperature in rats

Cited by 46 publications

References 31 publications

Antagonism of corticotropin-releasing hormone alters serotonergic-induced changes in brain temperature, but not sleep, of rats

Antagonism of corticotropin-releasing hormone alters serotonergic-induced changes in brain temperature, but not sleep, of rats

The Involvement of Brain Monoamines in the Onset of Hyperthermic Central Fatigue

MWCNT-Chitosan-ZrO2 Nanocomposite Modified Sensor for Sensitive and Selective Electrochemical Determination of Serotonin

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