EXTRACELLULAR-MATRIX COMPONENTS IN THE HEART OF THE WHITE BASS, MORONE CHRYSOPS (RAFINESQUE)

The distribution of laminin, collagen type IV, collagen bundles, prote oglycans, elastin, and periodic acid - Schiff's moieties (glycoprotein s) within the heart of the adult white bass, Morone chrysops (Rafinesq ue), was investigated by means of immunohistochemical and histological techniques. Laminin and collagen type IV were heavily expressed withi n the epimysium and the basal lamina of the lining epicardial epitheli um and valvular endothelium, moderately expressed within the myocardiu m, and slightly expressed within the subendocardium. This co-localized distribution of laminin and collagen type IV corresponds to the bioch emically unidentified basal and external lamina observed in the hearts of other fish by previous ultrastructural investigations and is simil ar to the distribution observed in the hearts of birds and mammals. Al so demonstrated was an interesting division of connective tissue compo nents along the longitudinal axis of the atrioventricular valve, which is most likely intimately involved with the effective functioning and durability of the valve.