Noradrenergic and adrenergic neurons strongly express c-FOS after muscimol inhibition of the DPGi.

<p>Double-immunostained sections with TH (brown cytoplasmic staining) and c-FOS (black nuclear staining) at the level of A6 (<b>A</b>,<b>D</b>), A5 (<b>B</b>,<b>E</b>) and A1/C1 (<b>C</b>,<b>F</b>) noradrenergic cell groups after NaCl (top panel) or muscimol (bottom panel) injection in the DPGi. Black arrows point out double labeled neurons whereas black arrowheads and double arrowheads indicate TH singly and c-FOS singly labeled neurons, respectively. Scale bars, 50 µm for low power and 200 µm for high power photomicrographs in <b>B</b>, <b>C</b>, <b>E</b> and <b>F.</b> Abbreviations: 4V, 4th ventricle; A1/C1, A1 noradrenergic and C1 adrenergic groups; A5, A5 noradrenergic group; Gi, gigantocellular reticular nucleus; IO, inferior olive; PnC, pontine reticular nucleus, caudal part; py, pyramidal tract; sp5, spinal trigeminal tract; Sp5O, spinal trigeminal nucleus, oral part.