Male post-embryonic Ilp7 neurons are serotonergic and glutamatergic and innervate the seminal vesicle with type II-like NMJs. (A,A′) In males, OK371-GAL4,UAS-nEGFP (VGlut reporter) was not expressed in Fkh-positive embryonic Ilp7 neurons of the ventral (Ven, arrows) cluster but was expressed in Fkh-negative post-embryonic Ilp7 neurons of the dorsal (Dor) cluster. (B,B′) Serotonin (5-HT) is expressed by post-embryonic (B′) but not embryonic (B) Ilp7 neurons. (C-J) Images of Ilp7 neuronal synapses on the seminal vesicle. Ilp7-GAL4,UAS-mCD8::GFP-labeled axons and synaptic boutons co-labeled with anti-HRP (general neuronal marker) and anti-Ilp7 (C), anti-serotonin (5-HT) (D), anti-VGluT (E) and anti-Bruchpilot (Brp) (F). (G) Neither CD8-GFP-Shaker nor Dlg (type I NMJ markers) were localized to Ilp7 synaptic boutons. (H-J) Low level GluRIIC (H) and GluRIIA (I) were observed at most Ilp7 synapses, but GluRIIB expression was not (J). Arrows/arrowheads indicate representative neurons of each Ilp7 subset.