Qualitative observations on fine structural changes with age in the ventricular myocardial cells of a teleost, Pleuronectes platessa L.

Ultrastructural studies on the ventricular myocardial cells of a sample of 10...16 year old plaice (Pleuronectes platessa L.) reveal an increase in the amount of glycogen particles, the presence of primary and secondary lysosomes and small intracellular vacuoles. Mitochondria were predominantly swollen and many were observed in different stages of degeneration and degradation by lysosomes within autophagic vacuoles. Myofilaments were not as distinctly defined as in the control group of 3...5 year old fish in which also the above features were not apparent. Such features are therefore interpreted as being age-associated.