Studies on blood and cardiac activity of the heart from Concholepas concholepas

Abstract

The paucity of data on the physiology of the Chilean invertebrates induced us to study the blood and cardiac activity of the mollusc Concholepas concholepas, commonly known as the “loco” (Chilean abalone). Electrolytes, protein content and composition as well as the blood cells of this mollusc proved to be very similar to those of other invertebrates (molluscs and arthropods). Blood proteins werc separated and characterizcd by chromatography on DEAE-cellulose and paper electrophoresis. The results showed that 90-96°/o of these proteins corresponded to hemocyanin and that the remaining 4 - 10°/o were probably of an intracellulax
origin. The gross anatomy of the heart shows the presence of one atrium and one ventricle. The heart tissue is made up of profusely anastomosed cardiac muscle fibers, amongst which intramural nerve cells can be found. The striated muscle cells are organized into three layers which are separated by connective tissue. Glycogen can be observed within the muscle fibers. The inner and outer surfaces of the heart are covered by epithelial membranes. The electrical and mechanical activity of the ventricle is irregular and arhythmic. These findings are probably due to cholinergic-like cardioinhibitory activity of the nerve cells within the tissue, since atropine regularized and accelerated the heart rhythm. The lack of an oscillatory potential as well as the responses to Chemical mediators such as acetylcholine and noradrenaline indícate that the heart of the heart of this mollusc is miogenic.