Evidence that large synaptic vesicles containing substance P and small synaptic vesicles have a surface antigen in...

Synaptic vesicles were purified from rat brain synaptosomes by osmotic lysis and chromatography on CPG-3000 controlled-pore glass beads. Large (approximately 100 nm) synaptic vesicles containing the peptide substance P (SP) were shown to be immunoprecipitated by a monoclonal antibody previously shown by W.D. Matthew, L. Tsavaler and L.F. Reichardt (J. Cell Biol., 91 (1981) 257-269) to selectively immunoprecipitate small (approximately 50 nm) synaptic vesicles from brain. Precipitation of SP-containing vesicles showed a saturable dependence on antibody concentration. These findings constitute direct, immunochemical evidence that large, peptidergic synaptic vesicles and small synaptic vesicles from brain have a surface antigen in common.