Different antibodies show different features at Drosophila NMJs
Anti-Horseradish peroxidase (HRP) labels neuronal surfaces1, anti-Discs large (Dlg) mainly postsynaptic cytoskeletal structures2, anti-Synapsin (Syn)3 presynaptic vesicle pools, anti-Synaptotagmin (Syt)4 presynaptic vesicle pools and synaptic membranes, nc825 labels presynpatic active zones, anti-Glutamate receptor (GluR)6 labels postsynaptic ionotropic transmitter receptors, and anti-Shaker (Sh)7 postsynaptic voltage gated potassium channels.

1) Jan, Y.-N. & Jan, L.-L. Antibodies to horseradish peroxidase as specific neuronal markers in Drosophila and grasshopper embryos. Proc. Natl. Acad. Sci. USA 79, 2700-2704 (1982).
2) Budnik, V. et al. Regulation of synapse structure and function by the Drosophila tumor suppressor gene dlg. Neuron 17, 627-40 (1996).
3) Klagges, B. R. E. et al. Invertebrate Synapsins: a single gene codes for several isoforms in Drosophila. J. Neurosci. 16, 3154-3165 (1996)
4) Littleton, J. T., Bellen, H. J. & Perin, M. S. Expression of synaptotagmin in Drosophila reveals transport and localization of synaptic vesicles to the synapse. Development 118, 1077-1088 (1993).
5) Erich Buchner, unpublished.
6) Schuster, C. M. et al. Molecular cloning of an invertebrate glutamate receptor subunit expressed in Drosophila muscle. Science 254, 112-114 (1991).
7) Tejedor, F. J. et al. Essential role for dlg in synaptic clustering of Shaker K+ channels in vivo. J. Neurosci. 17, 152-159 (1997).