The selective effects of a monoclonal antibody against neural growth-related protein A3G7 on central mechanisms of several types of defensive behavior in adult rats.

Studies were carried out into the effects of monoclonal antibodies to protein A3G7, which is associated with the differentiation of cerebellar and hippocampal neurons, on the development, retention, and reproduction of a habituated acoustic startle response and freezing behavior in rats. Application of monoclonal antibody (50 ng) to the vermis of the cerebellum selectively disrupted the retention of long-term habituation of the acoustic startle response, while a higher dose (5 micrograms) inhibited both retention of long-term habituation of the acoustic startle response and conditioned freezing behavior. Monoclonal antibody (10 micrograms) disrupted the development and retention of short-term and long-term extinction of the acoustic startle response, as well as conditioned freezing behavior. These data provide experimental support for the systemogenesis hypothesis of behavioral acts and for the concept that there is a single molecular basis for development and learning.