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Cellular ultrastructure and catecholamine histofluorescence of the heart of the Australian lungfish, Neoceratodus forsteri
Author(s) -
Chopin L. K.,
Bennett M. B.
Publication year - 1995
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1052230207
Subject(s) - biology , ultrastructure , lungfish , anatomy , vesicle , caveolae , sarcomere , catecholamine , endoplasmic reticulum , cytoplasm , microbiology and biotechnology , atrium (architecture) , myocyte , medicine , endocrinology , fish <actinopterygii> , genetics , signal transduction , membrane , fishery , atrial fibrillation
Ultrastructural descriptions of the dipnoan heart are lacking. Many ultrastructural features of the heart of the Australian lungfish, Neoceratodus forsteri , resemble those of other lower vertebrates. The epicardial cells appear to be adapated for the exchange of material with the pericardial fluid. The most prominent features of the endocardial cells are numerous moderately electron‐dense vesicles found within the cytoplasm. These organelles might have an endocrine function. The myocardiocytes are typically small. The banding pattern of the sarcomere is shared with most fish. The intercalated disc has a convoluted path and consists of desmosomes and fascia adherens. Caveolae are a prominent feature of the sarcoplasm. The sarcoplasmic reticulum is sparse, and T‐tubules are lacking. Atrial myocardial dense bodies occur in vast numbers throughout the atrium and are occasionally seen in the ventricle. These vesicles are chromaffin‐positive but fail to show catecholamine fluorescence. They are likely to contain peptides related to ANP. Subendothelial cells exhibiting catecholamine‐specific fluorescence are scattered throughout the atrium. Ultrastructurally these cells contain many chromaffin‐positive granules. Chromaffin cells represent another cell type with a probable endocrine function within the heart of N. forsteri . © 1995 Wiley‐Liss, Inc.