Original scientific paper

https://doi.org/10.24099/vet.arhiv.160624

Leucine-enkephalin is co-expressed with substance P, galanin and somatostatin in the ovine pancreas

Aleksandra Górska ; Department of Animal Anatomy and Histology, Faculty of Veterinary Medicine, University of Life Sciences, Lublin, Poland
Anna Zacharko-Siembida ; Department of Animal Anatomy and Histology, Faculty of Veterinary Medicine, University of Life Sciences, Lublin, Poland
Marcin B. Arciszewski ; Department of Animal Anatomy and Histology, Faculty of Veterinary Medicine, University of Life Sciences, Lublin, Poland

Abstract

Leucine-enkephalin (Leu-Enk) is an endogenous opioid peptide that binds to opioid receptors. Leu-Enk is widely distributed in the central and peripheral nervous system. The aim of the present immunofluorescence study was to examine the distribution of Leu-Enk-immunoreactive (IR) neuronal elements in the ovine pancreas. Using double immunohistochemical staining, the co-localization of Leu-Enk with galanin, somatostatin and substance P was also studied. In the intrapancreatic ganglia, immunoreactivity to Leu-Enk was found in 64.9 ± 1.7% of neurons. Small arterioles and the ductal system were innervated by numerous Leu-Enk-IR nerve terminals. Moderate Leu-Enk-IR nerve fibres surrounded the islets of Langerhans but none of them penetrated into spaces between endocrine cells. In 66.7 ± 4.3% of Leu-Enk-immunoreactive intrapancreatic neurons, expression of galanin was found. A statistically smaller subpopulation of Leu-Enk-IR intrapancreatic neurons (37.4 ± 6.2%) exhibited immunoreactivity to SP. The expression of somatostatin was detected in the relatively smallest group (21.2 ± 3.8%) of Leu-Enk-positive intrapancreatic neurons. Co-expression of Leu-Enk and SP was detected in nerve terminals encircling the pancreatic small arterioles, connective tissue and ducts. Leu-Enk-positive nerve fibres around the islets of Langerhans were not immunoreactive for SP. None of the Leu-ENK-positive nerve fibres around the islets of Langerhans co-stored somatostatin. In general, there was also no co-localization between Leu-Enk and somatostatin in nerve terminals supplying small arterioles and veins. Co-expression of GAL and Leu-Enk was observed well in nerve fibres encircling the blood vessels, but not in nerve fibres of the connective tissue. We conclude that abundant immunoreactivity to Leu-Enk in the ovine pancreas and the co-localization of Leu-Enk with other regulatory neuropeptides may reflect the possible involvement of Leu-Enk as a regulator of the exocrine and endocrine pancreatic functions, as well as in regulation of pancreatic blood flow.

Keywords

opioid peptide; sheep; pancreas; leucine-enkephalin; intrapancreatic ganglia; immunohistochemistry

Hrčak ID:

186220

URI

https://hrcak.srce.hr/186220

Publication date:

6.9.2017.

Article data in other languages: croatian

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