The effect of anti-synaptosomal membrane antibodies of neurotransmitter uptake.
Antibodies raised against synaptosomal plasma membranes of rat hippocampus (anti-HPC IgG) caused inhibition of [3H]noradrenaline, [3H]5-hydroxytryptamine, [3H]GABA and [3H]aspartate uptake into S1 fractions and slices of hippocampus and cerebral cortex, but not those of caudate nucleus and hypothalamus. Similar inhibition was not observed on using antibodies against synaptosomal membranes of rat caudate nucleus. Anti-HPC IgG raised against synaptosomal membranes of hippocampus failed to alter both spontaneous and K+-evoked release of [3H]noradrenaline. They did not interfere with the binding of [3H]desipramine (the potent noradrenaline-uptake inhibitor) and with the binding of [3H]dihydroalprenolol, thus excluding any interaction of the antibodies with drug receptors which are located on either the pre- or postsynaptic membrane. The anti-HPC IgG inhibit the enzymatic activity of [Na+-K+-]ATPase by 30% upon incubation of the antibodies with crude membrane preparations. A comparison of their inhibitory effects with those of the neurotoxin 6-hydroxydopamine suggests that the corresponding hippocampal specific antigens are located at a presynaptic site.