Antibodies to synaptosomal membranes of rat hippocampus and caudate nucleus: Immunological and behavioral characteristics

Abstract

Synaptosomal plasma membranes (SPMs) from the caudate nucleus (Cd) and hippocampus (HPC) were used as immunogens against which antisera were raised in rabbits (anti-HPC and anti-Cd serum, respectively). All immunologic reactivity of anti-Cd serum could be neutralized by absorption of the serum with either HPC-SPMs or Cd-SPMs. Similarly, all reactivity of the anti-HPC serum was neutralized by absorption with HPC-SPMs. On the other hand, a substantial part of the reactivity of anti-HPC serum remained after absorption with Cd-SPMs. These results indicate that the HPC-SPM preparation contains antigenic determinants which are absent from Cd-SPM preparation. When the immunoglobulin type G (IgG) fractions isolated from anti-HPC serum and anti-Cd serum were injected daily for 14 days into neonatal rats, they caused behavioral deficits which were observed in adulthood. No differences in general activity or in open-field behavior were found between those animals and controls. However, rats which had been injected for 14 days with anti-HPC IgG showed impairments in reversal learning in a T maze, in the retention of a passive avoidance task and in the acquisition of active avoidance. Rats injected with anti-Cd IgG showed much smaller impairments.