Extracellular matrix components in the heart of the white bass, Morone chrysops (Rafinesque)

The distribution of laminin, collagen type IV, collagen bundles, proteoglycans, elastin, and periodic acid–Schiff's moieties (glycoproteins) within the heart of the adult white bass, Morone chrysops (Rafinesque), was investigated by means of immunohistochemical and histological techniques. Laminin and collagen type IV were heavily expressed within the epimysium and the basal lamina of the lining epicardial epithelium and valvular endothelium, moderately expressed within the myocardium, and slightly expressed within the subendocardium. This co-localized distribution of laminin and collagen type IV corresponds to the biochemically unidentified basal and external lamina observed in the hearts of other fish by previous ultrastructural investigations and is similar to the distribution observed in the hearts of birds and mammals. Also demonstrated was an interesting division of connective tissue components along the longitudinal axis of the atrioventricular valve, which is most likely intimately involved with the effective functioning and durability of the valve.