TY - JOUR T1 - A Serial Multiplex Immunogold Labeling Method for Identifying Peptidergic Neurons in Connectomes JF - bioRxiv DO - 10.1101/027458 SP - 027458 AU - Réza Shahidi AU - Elizabeth A. Williams AU - Markus Conzelmann AU - Albina Asadulina AU - Csaba Verasztó AU - Sanja Jasek AU - Luis A. Bezares-Calderón AU - Gáspár Jékely Y1 - 2015/01/01 UR - http://biorxiv.org/content/early/2015/11/27/027458.abstract N2 - Electron microscopy-based connectomics aims to comprehensively map synaptic connections in neural tissue. However, current approaches are limited in their capacity to directly assign molecular identities to neurons. Here, we use serial multiplex immunogold labeling (siGOLD) and serial-section transmission electron microscopy (ssTEM) to identify multiple peptidergic neurons in a connectome. The high immunogenicity of neuropeptides and their broad distribution along axons, allowed us to identify distinct neurons by immunolabeling small subsets of sections within larger series. We demonstrate the scalability of siGOLD by using 11 neuropeptide antibodies on a full-body larval ssTEM dataset of the annelid Platynereis. We also reconstruct a peptidergic circuitry comprising the sensory nuchal organs, found by siGOLD to express pigment-dispersing factor, a circadian neuropeptide. Our approach enables the direct overlaying of chemical neuromodulatory maps onto synaptic connectomic maps in the study of nervous systems. ER -