Immediate response to light of rat pineal melatonin rhythm: analysis by in vivo microdialysis

Kanematsu, Nobue; Honma, Sato; Katsuno, Yumiko; Honma, Ken‐ichi

doi:10.1152/ajpregu.1994.266.6.r1849

Cited by 14 publications

(17 citation statements)

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“…Contrary to findings of Kanematsu et al. [20] we did not find any long‐term alteration of the melatonin rhythm, when the light pulse was given before midnight (ZT 20). Very likely we had no such effect because our experiment was carried out in continued LD cycles, while Kanematsu et al.…”

Section: Discussioncontrasting

confidence: 99%

“…Similar findings have been reported by Kanematsu et al. [20] for the melatonin release. These different effects of light on melatonin release may result from the circadian change of sensitivity in the light pathway [33, 34].…”

Section: Discussionsupporting

confidence: 92%

“…Kanematsu et al. [20] observed similar phase advances in rats, although they used a different protocol and released the animals in constant darkness after the light pulse. This means that even despite a present entrainment stimulus, namely the LD cycle, light at night has an enormous impact on the clock.…”

Section: Discussionmentioning

confidence: 96%

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Trans‐pineal microdialysis in the Djungarian hamster (Phodopus sungorus): a tool to study seasonal changes of circadian clock activities

Herwig¹,

Pévet²,

Bothorel³

et al. 2005

Journal of Pineal Research

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The Djungarian hamster is a highly seasonal small mammal. The rhythmic secretion of melatonin by the pineal gland is under control of the circadian clock, conveying the photoperiodic message to the organism. Trans-pineal microdialysis permits the in vivo study of this well-defined and precise clock output by measuring melatonin release directly in the pineal gland. The aim of this study was to adapt this method to the Djungarian hamster in order to monitor clock properties during photoperiodic changes. Male adult Djungarian hamsters were kept in a long photoperiod (LD 16:8) and melatonin release was measured hourly during the dark period for several weeks. Melatonin showed a regular secretion between ZT 17 and ZT 23.5 whereas the amplitude became stable only after the third day of perfusion. To test how quickly changes in melatonin profile can be measured, 15-min light pulses were given at different time points throughout the scotophase. Light-pulses immediately interrupted melatonin secretion at any time point during the scotophase and the temporal resolution for measurement could be reduced to 30 min. In accordance with studies in the rat, long-term effects of light on the clock could only be observed when a light pulse was administered in the second half of the night. For the first time we established a method to measure precisely a direct and reliable clock-output in a highly seasonal species which allows us now to study the circadian and seasonal properties of the clock in detail.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionsupporting

confidence: 92%

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Trans‐pineal microdialysis in the Djungarian hamster (Phodopus sungorus): a tool to study seasonal changes of circadian clock activities

Herwig¹,

Pévet²,

Bothorel³

et al. 2005

Journal of Pineal Research

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“…By contrast, pulses administered after midnight provoked no change in the NAT rise on the next night, but the timing of the rise had advanced by day 4 in animals pulsed between ZT 21 and ZT 23. Kanematsu and coworkers utilized in vivo microdialysis and a similar lighting protocol and reported a 0.94-h phase delay in the melatonin rhythm on the night after a 200 lux/3 min pulse at ZT 17 (Kanematsu et al, 1994). A similar pulse at CT 22 resulted in an immediate advance of 0.81 h on the night after the stimulus, in contrast to the NAT results (Illnerova et al, 1989) and observations in the current study.…”

Section: Discussioncontrasting

confidence: 79%

Phase Response Relationships between Light Pulses and the Melatonin Rhythm in Rats

Stepien

Kennaway

2001

J Biol Rhythms

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There is some controversy whether phase response curves constructed from studies conducted after acute release into constant darkness (Type II) or after prolonged constant darkness are comparable. This study investigated the effects of brief low-intensity light pulses on the onset of 6-sulphatoxymelatonin excretion in rats 48 to 60 h after lights-off and after 14 days of continuous darkness. In the former condition, maximum phase delays occurred between 4 and 6 h after expected lights-off, but no phase advances were observed within 2 days of the presentation of the stimulus. When the times of the pulses were plotted in relation to the individual onsets, peak light-induced phase delays occurred 0 to 2 h after melatonin onset. After 14 days in continuous darkness, the peak phase delays also occurred 0 to 2 h after melatonin onset and were slightly but significantly smaller. No significant phase advances were observed. In a separate small series of experiments, the temperature rhythm of rats was shown to be delayed by a comparable degree to that of melatonin by light pulses 2 and 4 h after expected lights-off under the Type II conditions. It is concluded that phase response curves conducted under Type I and Type II conditions are comparable.

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“…In the pineal gland of rats, the microdialysis technique has been applied in attempts to monitor a 24-hr pattern of melatonin (22)(23)(24)(25). However, implanting the microdialysis probe directly into the very tiny pineal gland of a mouse is more difficult.…”

mentioning

confidence: 99%

Bimodal circadian secretion of melatonin from the pineal gland in a living CBA mouse

Nakahara

Nakamura

Iigo

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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Circadian melatonin secretion is the best-known output signal from the circadian pacemaker in the suprachiasmatic nucleus that indicates internal conditions of the body. We have established a system that enables long-term monitoring of melatonin secretion by implanting a transverse microdialysis probe in or near the pineal gland in a freely moving mouse. This in vivo method enabled continuous measurement of melatonin secretion over a period of >20 days in individual CBA mice, with simultaneous recording of the locomotor activity. Pineal melatonin secretion was completely matched to the circadian change of locomotor activity, and for the light-induced phase shift, the shift of melatonin secretion was clearer than the shift of locomotor rhythm. This analysis allowed us to detect rhythm with a high sensitivity: two peaks of daily secretion were observed, with the first small peak at the day-night transition time and the second large peak at midnight. The large nighttime peak was suppressed by tetrodotoxin, a Na ؉ channel blocker, and enhanced by both phenylephrine and isoproterenol, ␣-and ␤-adrenergic agonists, whereas daytime melatonin levels were not affected by tetrodotoxin infusion. This finding suggests that, in CBA mice, melatonin release at night is activated by adrenergic signaling from the superior cervical ganglion, but the enhancement of melatonin during daytime is not mediated by neuronal signaling.circadian rhythm ͉ locomotor activity ͉ microdialysis I n mammals, most physiological and behavioral events are subject to well controlled daily oscillations, and these rhythms are generated by the circadian clock in the suprachiasmatic nucleus (SCN) (1, 2). Recent progress in the genetic dissection of the clock genes has provided an outline of the molecular machinery of clock oscillation: the generation of rhythm begins at the transcription͞ translation feedback loops of clock genes (3-6). The dynamics of this core oscillatory loop is now monitored in transgenic animals carrying the mPer1 promoter driven luciferase reporter (7-9).From the Drosophila to mammals, an astonishing feature in circadian biology is that the rhythm of this gene transcription is integrated to cell, tissue, and organ, and finally to coordinated temporal organization at the system level. Because the molecular monitoring of gene transcription is now available, real-time rhythm-effector analysis is inevitable to clarify the linkage from the molecular oscillator to the effector. Of the circadian effectors, the behavioral sleep-awaking rhythm is the best known, and locomotor activity is used as a noninvasive output showing the clear-cut circadian expression in living mice. However, the behavioral rhythm is only one output of the SCN oscillator, and the real-time nature of the time information with regard to the body system has not been previously addressed.In our search for a measure of the circadian output that indicates internal conditions of the body, we focused on melatonin (N-acetyl5methoxytryptamine), a hormone primarily secreted by t...

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Immediate response to light of rat pineal melatonin rhythm: analysis by in vivo microdialysis

Cited by 14 publications

References 0 publications

Trans‐pineal microdialysis in the Djungarian hamster (Phodopus sungorus): a tool to study seasonal changes of circadian clock activities

Trans‐pineal microdialysis in the Djungarian hamster (Phodopus sungorus): a tool to study seasonal changes of circadian clock activities

Phase Response Relationships between Light Pulses and the Melatonin Rhythm in Rats

Bimodal circadian secretion of melatonin from the pineal gland in a living CBA mouse

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