Journal ArticleDOI
Microdialysis of melatonin in the rat pineal-gland - methodology and pharmacological applications
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TLDR
It is concluded that neuronal activity is necessary to synthesize melatonin and that during daytime no net neuronalactivity is present.Abstract:
The present study describes the development of a new technique to measure melatonin contents in the pineal gland of freely moving rats, by means of on-line microdialysis. The transcerebral cannula was modified, and a sensitive assay of melatonin, using HPLC with fluorimetric detection, was set up. With this system it is possible to monitor the melatonin levels on-line in the pineal gland during day- and nighttime. The nightly increase in melatonin release was recorded. Tetrodotoxin had an inhibitory effect on nighttime levels, whereas even high concentrations did not alter the daytime level. From this we conclude that neuronal activity is necessary to synthesize melatonin and that during daytime no net neuronal activity is present. Melatonin levels could be greatly enhanced by systemic administration of the beta-agonist isoprenaline (ISO). Also, local infusion of ISO or 8-bromoadenosine 3',5'-cyclic monophosphate, an analogue of the second messenger cyclic AMP, resulted in increased melatonin levels, demonstrating the presence of beta-adrenergic receptors, coupled to a cyclic AMP-based second messenger system, on the pineal gland. Injection of phenylephrine had no effect on daytime levels. Only when administered during ISO-induced stimulation of melatonin release did it enhance this stimulated release. This proved the regulatory role of alpha1-receptors on pinealocytes. The method presented is of special interest for investigating the innervation of the pineal gland and the biochemical processes that regulate the biosynthesis of melatonin. Also, for studies on the diurnal rhythms of melatonin release and factors that influence these rhythms in freely moving animals, this model will be of great value.read more
Citations
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Journal ArticleDOI
Generation of the Melatonin Endocrine Message in Mammals: A Review of the Complex Regulation of Melatonin Synthesis by Norepinephrine, Peptides, and Other Pineal Transmitters
TL;DR: The aim of this review is to gather together early and recent data on the effects of the nonadrenergic transmitters on modulation of melatonin synthesis, which reveals the variety of inputs that can be integrated by the pineal gland; what elements are crucial to deliver the very precise timing information to the organism.
Journal ArticleDOI
Brain microdialysis and its application for the study of animal behaviour.
TL;DR: It is concluded that microdialysis is at presently the most versatile and practical method to study the chemistry of behaviour and it is to be expected that it will soon be a routine methodology in behavioural research.
Journal ArticleDOI
Methodological issues in microdialysis sampling for pharmacokinetic studies.
TL;DR: With the progress of analytical methodology, especially with respect to low volume/low concentration measurements and simultaneous measurement of multiple compounds, the applications and importance of the microdialysis technique in pharmacokinetic research will continue to increase.
Journal ArticleDOI
Suprachiasmatic control of melatonin synthesis in rats: inhibitory and stimulatory mechanisms
Stephanie Perreau-Lenz,Andries Kalsbeek,Marie-Laure Garidou,Joke Wortel,Jan van der Vliet,Caroline van Heijningen,Valérie Simonneaux,Paul Pévet,Ruud M. Buijs +8 more
TL;DR: Results show that ablation of the SCN not only removes an inhibitory input but also a stimulatory input to the melatonin rhythm generating system, which could be of a great interest for the mechanism of adaptation to day‐length and seasons.
Journal ArticleDOI
Melatonin sees the light: blocking GABA‐ergic transmission in the paraventricular nucleus induces daytime secretion of melatonin
Andries Kalsbeek,Marie-Laure Garidou,I.F. Palm,J. van der Vliet,Valérie Simonneaux,Paul Pévet,Ruud M. Buijs +6 more
TL;DR: It is shown in the rat that bilateral abolition of γ‐aminobutyric acid (GABA), but not vasopressin, neurotransmission in an SCN target area, during (subjective) daytime results in increased pineal melatonin levels, substantiates the existence of a major inhibitory SCN output controlling the circadian melatonin rhythm.
References
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Journal ArticleDOI
The Rat Brain in Stereotaxic Coordinates, George Paxinos, Charles Watson (Eds.). Academic Press, San Diego, CA (1982), vii + 153, $35.00, ISBN: 0 125 47620 5
TL;DR: It is shown here how the response of the immune system to repeated exposure to high-energy radiation affects its ability to discriminate between healthy and diseased tissue.
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Pineal Melatonin: Cell Biology of Its Synthesis and of Its Physiological Interactions*
TL;DR: The pineal gland can be rapidly removed from rodents with minimal damage to adjacent neural structures using a specially designed trephine, and since the mid 1960s, research on the gland has become a very active area of investigation.
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Trans-striatal dialysis coupled to reverse phase high performance liquid chromatography with electrochemical detection: a new method for the study of the in vivo release of endogenous dopamine and metabolites
Assunta Imperato,G. Di Chiara +1 more
TL;DR: The biochemical and histological results obtained indicate that the method is suitable to estimate in the rat the changes in the release of endogenous DA and its metabolites which take place in vivo under administration of centrally acting drug.
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Scope and limitations of in vivo brain dialysis: a comparison of its application to various neurotransmitter systems.
TL;DR: It is concluded that dopamine, noradrenaline and acetylcholine found in the dialysate are directly derived from neurotransmission, whereas the overflow of excitatory amino acid neurotransmitters is related to neurogenic as well as to metabolic events.