Galanin regulates blood glucose level in the zebrafish: a morphological and functional study.
The present study has demonstrated the galaninergic innervation of the endocrine pancreas including sources of the galaninergic nerve fibers, and the influence of galanin receptor agonists on blood glucose level in the zebrafish. For the first time, a very abundant galaninergic innervation of the endocrine pancreas during development is shown, from the second day post-fertilization to adulthood. The fibers originated from ganglia consisting of galanin-IR, non-adrenergic (non-sensory) neurons located rostrally to the pancreatic tissue. The ganglia were found on the dorsal side of the initial part of the anterior intestinal segment, close to the intestinal branch of the vagus nerve. The galanin-IR neurons did not show immunoreactivity for applied antibodies against tyrosine hydroxylase, choline acetyltransferase, and vesicular acetylcholine transporter. Intraperitoneal injections of galanin analog NAX 5055 resulted in a statistically significant increase in the blood glucose level. Injections of another galanin receptor agonist, galnon, also caused a rise in blood glucose level; however, it was not statistically significant. The present findings suggest that, like in mammals, in the zebrafish galanin is involved in the regulation of blood glucose level. However, further studies are needed to elucidate the exact mechanism of the galanin action.
Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland. piotr.podlasz@uwm.edu.pl.
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http://orcid.org/0000-0002-9162-5449
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Podlasz
Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland.
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Jakimiuk
Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland.
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Chmielewska-Krzesinska
Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland.
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Kasica
Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland.
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Nowik
Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland.
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Kaleczyc
D000818:Animals; D001786:Blood Glucose / Q000032:analysis* / Q000187:drug effects; D005260:Female; D019004:Galanin / Q000031:analogs & derivatives / Q000494:pharmacology*; D005726:Ganglia, Parasympathetic / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism*; D055666:Lipopeptides / Q000494:pharmacology; D008297:Male; D044088:Receptors, Galanin / Q000819:agonists*; D015027:Zebrafish
D001786:Blood Glucose; D055666:Lipopeptides; C000604069:NAX 5055; D044088:Receptors, Galanin; D019004:Galanin
Blood glucose; Galanin; Insulin; Parasympathetic ganglia; Somatostatin; Zebrafish