Neurofilamentous changes in goldfish (Carassius auratus L.) brain in relation to environmental temperature.

The presence of neurofilaments in the synaptic boutons in the brains of goldfish maintained at 5 degrees C for 177 days or more is reported. Neurofilaments are not found in boutons of control fish kept at 15degreesC. It is suggested that the neurofilaments may be equated with neurofibrillary rings seen by light microscopy. Neurofilaments have been implicated in axoplasmic transport and, therefore, irregularities in the occurrence or appearance of these filaments may reflect alterations in their functions. The unusual occurrence of neurofilaments in the boutons of cold temperature goldfish may be an expression of early degenerative changes or may represent a modification of axoplasmic transport. The suitability of goldfish as a model for the study of the functional effects of neurofibrillary/neurofilamentous accumulations is discussed.