Fig 1: Level of c-FOS expression in wake promoting systems after NaCl or muscimol injection in the DPGi.Photomicrographs showing double immunostained sections for c-FOS (black nuclear staining) and hypocretin (HCRT, A, B), histamine (HDC, C, D), serotonin (5-HT, E, F) and choline acetyltransferase (ChAT, G, H) (brown cytoplasmic staining) 3 h after NaCl (left panel) or muscimol (right panel) injection in the DPGi. The areas illustrated at high power magnification are depicted in a box on the low power photomicrographs. Black arrows point out double-labeled neurons. Black arrowheads show singly labeled neurons for HCRT, HDC, 5-HT or ChAT and double arrowheads c-FOS singly labeled neurons. Scale bars, 50 µm for high enlargements and 200 µm for low enlargements. Abbreviations: 3V, 3rd ventricle; Aq, aqueduct; DR, dorsal raphe; DTg, dorsal tegmental nucleus; f, fornix; LDTg, laterodorsal tegmental nucleus; mlf, medial longitudinal fasciculus; mt, mammillothalamic tract; opt, optical tract; PnC, pontine reticular nucleus, caudal part.