Efficient fluorescent labeling of DA neurons and their axons in AAV-LSL-mCherry injected DA neuron-specific Cre mice.

<p><b>(A)</b> Scheme for specific fluorescent labeling of DA neuron in mice expressing a DA neuron-specific Cre and stereotaxic injected in the mindbrain with a recombinant AAV vector expressing mCherry after a floxed STOP codon. <b>(B-G)</b> Fluorescent mCherry expression in DA cells of the midbrain (B-D) and DA fibers in the striatum (E-G) in sagittal sections of stereotaxic injected DAT-Cre mice. Expression was evaluated 1 (B,E), 3 (C,F) and 5 weeks (D,G) after injection. After 1 week, no expression could be detected in DA fibers of the striatum. Expression in DA fibers was saturated 5 weeks after injection. Scale bars = 200 μm (B-D); 20 μm (E-G). <b>(H-O)</b> Fluorescent mCherry expression in DA cells of the midbrain (H-K) and DA fibers in the striatum (L-O) after stereotaxic injection of TH-tTA/LC1 mice. Fluorescent expression was evaluated at the indicated time points in mice raised without DOX. Some mice were kept on DOX-containing food after the virus injection until analyzed (J, K, N, O). Scale bars = 200 μm (H-K); 20 μm (L-O). <b>(P and Q)</b> No fluorescent mCherry expression was detected in the lateral habenula (LHb) of AAV-LSL-mCherry injected DAT-Cre (P) and TH-tTA/LC1 (Q) mice after 5 weeks. Scale bars = 200 μm.