Fig. 5. Monoamine anatomy and release in the DCN.

(A) Schematic DCN circuit. Excitatory synapses are represented by filled circles, inhibitory synapses by open circles. Cartwheel cell somata are typically located near molecular/fusiform cell layer border.

(B) TH⁺ axonal fibers in the DCN. Image is a z-stack of a 50 μm confocal series. Greyscale inverted for clarity. Dashed lines denote layer borders. ML: molecular layer, FCL: fusiform cell layer, DL: deep layer.

(C) Z-stack of cartwheel cell filled with Alexa 594 in a slice from a TH-GFP animal. Recording pipette exits cell on left. GFP-TH⁺ axonal fibers are in green, cartwheel cell is filled with Alexa 594 (red).

(D) Single optical section of closest apposition of TH⁺ fiber and cartwheel cell axon.

(E) Fast-scan cyclic voltammetric recordings vs. time in DCN layers in response to local electrical stimulation in the same layer. Data are single traces all from one slice. Onset and offset of stimulation are indicated by the black bar. Layer abbreviations are as in (B).

(F) Summary of peak dopamine amplitudes in cochlear nucleus layers. Bars are SEM. Asterisk: p < 0.001. n = 12 slices. Layer abbreviations are as in (B).

(G) Top: Representative voltammagram recorded in the fusiform layer. Bottom: voltammagram in response to exogenous dopamine delivered via iontophoresis.

(H) Effect of GBR 12909 on voltammetric recordings in the fusiform layer. Data are single traces.