The immunohistochemical detection of metionin-enkephalin (met-ENK) in the entero-pancreatic system of some species of amphibians

Authors: Ioana Trandaburu¹*, Tiberiu Trandaburu²

Affiliation: ¹ Centre of Cytobiology, Institute of Biology, Bucharest, Romania; ² Laboratory of Histology and Embriology, Faculty of Sciences, University of Pitesti, Romania

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ABSTRACT. The immunoreactive structures for met-ENK and their incidence in the enteropancreatic system of four species of amphibians are described and evaluated semi-quantitatively for the first time. Thus, the immunoreaction was detected in both “ open “ and “ closed “ neuroendocrine elements disseminated randomly among the epithelial cells of the intestinal villi, in the ganglionic perikarya of the superficial mientheric plexus and the last but not the least, in their extensions encountered in the circular musculature, in submucosa and even in the villi axis’s of the enteric wall. In the newts pancreas solitary endocrine cells and in that of frogs small clusters of 3-5 immunostained cells, besides the fine profiles of perivascular, periductular and periacinar nerve fibers were identified. With the exception of several minor, species-specific differences and also of the taxon studied, the findings entirely support the concept of a good conservation of this opioid during phylogeny. The above results and their functional significances are discussed in connection with the findings reported not only in the mammalian gastro-entero-pancreatic (GEP) system but also in other glandular organs.

Keywords: metionin-enkephalin, met-ENK, enteropancreatic system, amphibians, immunohistochemistry