Technique for the simultaneous ultrastructural demonstration of anterogradely transported horseradish peroxidase and an immunocytochemically identified neuropeptide

In order to extend the information obtainable from ultrastructural studies of synaptic connectivity using either horseradish peroxidase tracing or immunocytochemistry alone, we have developed a method of combining these two procedures. Thus it has been possible to examine the characteristics of axon terminals of known origin forming synaptic contacts with cells of identified neuropeptide content.