Distribution of sNPF precursor immunoreactivity (sNPFp-IR) in relation to the ring gland and anterior aorta of the larva (anterior is up). A. sNPFp-IR (red) in brain and the corpora cardiaca (CC) portion of the ring gland and aorta (Ao). Immunolabeling is also seen in peduncle (P) and β and γ-lobes of the mushroom bodies. B and C. Dorsal (B) and ventral (C) aspects of retrocerebral complex in superimposed Nomarsky optics and immunofluorescence. In B the sNPFp-IR processes on the aorta are seen and in C the axons in the CC part of the ring gland. D. Double labeling with c929-Gal4-driven GFP (to display DIMM expression) and anti-sNPFp (magenta) shown from stack of confocal images. The c929 displays AKH-producing cells in the CC and median neurosecretory cells (MNC) in the pars intercerebralis some of which produce insulin-like peptides. Note sNPFp-IR axons invading the CC (asterisk) and a region adjacent ot the MNCs (arrow). The mushroom body calyx (Ca), peduncle (P) and lobes (α and γ) are indicated. E1 – E4. Confocal sections with details of sNPFp-IR fibers invading the corpora cardiaca portion of the ring gland. In E1 sNPFp processes are shown and in E2 c929-Gal4-driven GFP in neurosecretory cells in the CC and pars intercerebralis (MNC). Note dendritic branches of the neurosecretory cells (arrow). E3 shows the merged image with superposition of sNPFp-IR processes with endocrine cells in corpora cardiaca (CC and asterisk) and branches at arrow. E4 An enlarged detail of the dendrites of the MNCs in E3 (left hemisphere) with impinging sNPF-IR terminations. F Using a Dilp2-Gal4 to drive GFP it can be seen that the sNPF terminations superimpose on processes of the Dilp2-expressing neurons.