Orexine: Wirkungsspektrum und mögliche therapeutische Indikationen multifunktionaler Peptide

Zusammenfassung

Orexin-A und Orexin-B gehören zu einer neuen Gruppe von Peptiden, die zuerst im Hypothalamus der Ratte isoliert wurden. Sie wirken über G-Protein-gesteuerte Rezeptoren. Außer im lateralen Hypothalamus werden Orexine u.a. im Locus coeruleus, im Rückenmark und in den Nebennieren gebildet. Hypothalamische Efferenzen projizieren in multiple Kerngebiete, die den Energiehaushalt, die Psychomotorik, den Schlaf-Wach-Rhythmus und Kognition regulieren. Orexinrezeptoren werden im ZNS und in peripheren Organen (Niere, Nebennieren, Gonaden, Lunge, Darm) nachgewiesen. Da Orexine den Energiehaushalt und die Vigilanz des Organismus direkt beeinflussen, könnten sie für die Behandlung von Essstörungen und der Narkolepsie an Bedeutung gewinnen. Sie interagieren darüber hinaus mit einer Vielzahl von Transmittersystemen, welche das Gedächtnis, die Kognition, die Sexualität, den Affekt und die Psychomotorik kontrollieren.

Summary

Orexin-A and Orexin-B belong to a group of new peptides which were first detected in rat hypothalamus. They bind to G-protein coupled receptor systems. Apart from the lateral hypothalamus the peptides are also synthesized in the locus coeruleus, spinal cord or adrenal glands. Efferent fibres from the hypothalamus project to various nuclei which are involved in the control of feeding behaviour, sleep-wake cycle, motoric or cognitive function. Orexin receptors are found in the central nervous system and peripheral organs such as kidneys, adrenal glands, lung, testes/ovaries or the intestine. As Orexins directly influence the sleep-wake cycle and feeding behaviour they might be beneficial in the treatment of narcolepsia or eating disorders. Moreover, they interact with transmitter systems which are involved in the regulation of memory, cognitive or motoric function, affect and sexuality.

Schlüsselwörter

Orexine - Peptide - Energiehaushalt - Schlaf-Wach-Rhythmus

Keywords

Orexins - peptides - feeding behaviour - sleep-wake-cycle

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