Purification of specific antibody against aspartate and immunocytochemical localization of aspartergic neurons in the rat brain.

The distribution of L-aspartate known as a putative excitatory neurotransmitter in the central nervous system was investigated immunocytochemically in the rat brain. Anti-aspartate antiserum was raised in rabbits using L-aspartate covalently conjugated to rabbit serum albumin with glutaraldehyde as the immunogen and was found to be cross-reactive with an L-glutamate conjugate. Monospecific anti-L-aspartate antibody was successfully purified using affinity gels coupled with several amino acids including L-aspartate and L-glutamate and with the L-glutamate conjugate. Putative aspartergic neurons were generally immunoreactive to the purified antibody, but epithelia of the choroid plexus were also stained. These results show that the antibody is a useful tool for the immunocytochemical demonstration of possible aspartergic neurons in the central nervous system, although the immunochemical expression of L-aspartate not used as a neurotransmitter must be taken into consideration.