(A) 7 µm carbon fiber microelectrode inserted into the neuropil of an isolated ventral nerve cord for octopamine measurements. Comparison of puffed-on octopamine and different stimulations. Cyclic voltammograms (top), concentration vs time (center), and color plots (bottom) for (B) octopamine puffed into a larval ventral nerve cord, (C) CsChrimson (red light, 2 s) mediated release, and (D) P2X2 (0.5 pmol of ATP) mediated release in larval ventral nerve cord. All show similar peak characteristics with the primary peak around 1.1 V and secondary peak around 0.5 V with the slower scan waveform. Panels B-D Reproduced from Poojan Pyakurel,; Eve Privman Champaloux,; B. Jill Venton, ACS Chem. Neurosci., 2016, 7 (8), 1112–1119 (ref 193). Copyright 2016, American Chemical Society.