Structure of portal vein heart wall in the brown hagfish (Paramyxine atami)

Abstract

The portal vein heart (PVH) wall of the brown hagfish (Paramyxine atami) was observed by light and transmission electron microscopy. Cardiac musculature is well developed in the PVH wall. The myocytes possess arranged myofibrils in the cytoplasm. We suggest that the PVH may act as a pump in blood circulation from the intestines to the liver, as it does in other myxinoid species. Ultrastructural and immunohistochemical findings of the brown hagfish PVH myocytes also indicate that the PVH has an active contraction and atrial natriuretic polypeptide endocrine function. J Morphol 231:225–230, 1997. © 1997 Wiley‐Liss, Inc.