Figure 1.

Selective and functional expression of AlstR in rat A6 neurons. Fifteen days after LC injection of PRSx8-AlstR-GFP-LVV, there is robust selective expression in noradrenergic neuronal somata and processes. GFP expression (green), TH immunoreactivity (red), and overlaid images (right). 4^thV: fourth ventricle. Scale bar: 50 µm. (B) One neuron juxtacellular labelled in vivo with biocytin, exhibiting GFP and TH immunofluorescence (noradrenergic LC neuron). Scale bar: 20 µm. (C) Instantaneous firing frequency (bin width 10 ms) extracellularly recorded from the same labelled A6 neuron during baseline condition and in response to activation of peripheral chemoreceptors using KCN. This neuron also increased its firing frequency to 7% CO₂. Intracerebroventricular application of Alst rapidly and reversibly abolished its firing frequency.