Dopamine-immunoreactivity in the mushroom body.
All panels show a right brain hemisphere (dorsal to the top, medial to the right), except M-O (posterior to the top). Dopamine immunoreactivity is shown in magenta (A, D, G, J, M) and synapsin immunoreactivity in green (B, E, H, K, N). Corresponding merged images in C, F, I, L, O. A-C: Frontal sections through the lateral protocerebrum. DCa1 and 2 clusters are visible. D-F: Frontal sections through the vertical lobe. The distal part of the vertical lobe (VL) as well as the superior protocerebral neuropil are innervated by numerous dopamine-immunoreactive fibers. G-I: Horizontal sections through the tip of the vertical lobe, where dopamine-positive fibers are widely distributed. Dopamine-positive fibers in the calyx were faintly labeled by fluorescent immunolabeling technique (arrowheads in G) while those fibers were visualized by the HRP-mediated technique (G’), possibly because of the low content of dopamine. J-L: Horizontal sections through the calyx, ventral to panels G-I. DCa1 cell bodies project axons toward the anterior face of the vertical lobe bypassing the medial margin (arrowheads). These axons bear small fibers that invade layers of the vertical lobes that are immunolabeled by a synapsin antibody. DSP1 cell bodies are clustered in a region lateral to the vertical lobe. The anteriormost layer (γ layer) is predominantely innervated by immunoreactive fibers. M-O: Horizontal sections through the medial lobes (MLs). A band of dopamine-immunoreactive fibers invades the tip of the medial lobe parpendicularly to synapsin-positive layers (arrows). In a very marginal region around the midline, dopamine-positive fibers follow synapsin-positive layers. The DIP1 cell clusters are located in the inferior medial protocerebrum (IMP) anterior to the medial lobe (triangles). D, dorsal; KFL, Kenyon fiber layer; LCA, lateral calyx; LO, lobula; M, medial; MCA, medial calyx; NL, neuropil layer; P, posterior; SMP, superior medial protocerebrum; γ, γ layer; VLP, ventro-lateral protocerebrum. Scale bars = 100 μm.