Fig. 6.

Human iPSC-derived 5-HT specific neurons function rather via somatodendritic 5-HT release than synaptic transmission. A The presynaptic marker Bassoon is evenly expressed along soma and extensions of TPH2 + human iPSC-derived neurons. A´ Close-up image of (A). B Bassoon is localized in close proximity to the postsynaptic marker PSD-95 in dendrites and cell bodies of TPH2 + neurons. C dSTORM revealed a higher expression of Bassoon compared to the postsynaptic marker Homer in TPH2 + neurons. C´ Close-up images of (C). C´´ Example images illustrating contact points between Homer and Bassoon. Simplified schematic illustrations of Bassoon, PSD-95 and Homer expression in (D) volume transmission and (E) synaptic transmission. Scale bar: A 30 µm; A´ 10 µm; B 10 µm; C 2 μm; C´ 1 µm and C´´ 150 nm. Alexa Fluor 488 (PSD-95; MAP2), Alexa Fluor 532 (Homer; TPH2) and Alexa Fluor 647 (Bassoon) were used to visualize target proteins