Age related differences in binding of Concanavalin a to plasma membranes of isolated neurons

Neurons isolated from the lateral vestibular nucleus of young adult and senescent Fischer-344 rats were incubated with fluorescamine-labelled Concanavalin A (fl-Con A) alone, or following incubation in trypsin or Vibrio cholerae neuraminidase. They were then observed and photographed. Microdensitometric analysis of fluorescence micrographs showed that senescent rat neurons were significantly more fluorescent than those from young adult rats. Additionally, either patches or caps of fl-Con A were seen on the surface of neurons from senescent rats, while most young adult rat neurons bound fl-Con A uniformly. Pretreatment with trypsin or neuraminidase had no effect on the amount of fluorescence on the surface of senescent rat neurons, and only a slight effect on the surface distribution. Trypsin and neuraminidase treatments caused a significant increase in fluorescence on the neuronal plasma membranes of young adult rats and a rearrangement of the binding pattern in the majority of neurons observed.