title: Adrenergic activation of melatonin secretion in ovine pineal explants in short-term superfusion culture occurs via protein synthesis independent and dependent phenomena.
abstract: The ovine pineal is generally considered as an interesting model for the study on adrenergic regulation of melatonin secretion due to some functional similarities with this gland in the human. The present investigations, performed in the superfusion culture of pineal explants, demonstrated that the norepinephrine-induced elevation of melatonin secretion in ovine pinealocytes comprised of two subsequent periods: a rapid increase phase and a slow increase phase. The first one included the quick rise in release of N-acetylserotonin and melatonin, occurring parallel to elevation of NE concentration in the medium surrounding explants. This rapid increase phase was not affected by inhibition of translation. The second, slow increase phase began after NE level had reached the maximum concentration in the culture medium and lasted about two hours. It was completely abolished by the treatment with translation inhibitors. The obtained results showed for the first time that the regulation of N-acetylserotonin synthesis in pinealocytes of some species like the sheep involves the on/off mechanism, which is completely independent of protein synthesis and works very fast. They provided strong evidence pointing to the need of revision of the current opinion that arylalkylamines N-acetyltransferase activity in pinealocytes is controlled exclusively by changes in enzyme abundance.
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego Street 13, 10-719 Olsztyn, Poland.
authors.forename: Bogdan
authors.identifier: 0000-0003-2604-926X
authors.initials: B
authors.lastname: Lewczuk
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego Street 13, 10-719 Olsztyn, Poland.
authors.forename: Natalia
authors.identifier: 0000-0002-0748-7777
authors.initials: N
authors.lastname: Ziółkowska
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego Street 13, 10-719 Olsztyn, Poland.
authors.forename: Magdalena
authors.identifier: 0000-0001-6456-2502
authors.initials: M
authors.lastname: Prusik
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego Street 13, 10-719 Olsztyn, Poland.
authors.forename: Barbara
authors.identifier: 0000-0002-1712-5884
authors.initials: B
authors.lastname: Przybylska-Gornowicz
mesh_terms: D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D005260:Female; D006801:Humans; D008550:Melatonin / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000187:drug effects; D017208:Rats, Wistar; D011941:Receptors, Adrenergic / Q000378:metabolism*; D012701:Serotonin / Q000031:analogs & derivatives / Q000378:metabolism; D012756:Sheep; D013997:Time Factors; D046509:Tissue Culture Techniques
chemical_list: D011941:Receptors, Adrenergic; D012701:Serotonin; D000841:Anisomycin; D003513:Cycloheximide; D008550:Melatonin; C006389:N-acetylserotonin; D009638:Norepinephrine