Expression of the synaptic protein, synaptophysin, in injured pelvic ganglia. All pairs of micrographs showdouble-staining immunofluorescence for VIP (left) and synaptophysin(right). Panels a and b are from ganglia where the penile nerve wascut, whereas panels c and d are from penile nerve crush experiments. a, b. Synaptophysin-positive terminals are significantly reduced nearsome clusters of VIP neurons (many of which would be expected to beinjured) and in regions where there are many VIP fibres. Matchingpairs of arrows show examples of VIP somata. c, d. Little or nosynaptophysin expression is present in VIP fibres. Examples of VIP-positive, synaptophysin-negative fibres are indicated by arrows. Calibration bar represents: 40 μm (a, b) or 20 μm (c, d).