The effect of a single 47.5h episode of water restriction and drinking on the percentage of Fos-positive AVP or CRH neurons in the PVN. A single 47.5h episode of water restriction increased Fos expression in AVP magnocellular (pmPVN) (A), CRH parvocellular (mpPVN) (B), and AVP parvocellular (mpPVN) neurons (C). Drinking for 15 min reduced Fos expression in AVP magnocellular neurons (A) but not in CRH (B) or AVP parvocellular neurons (C). Values represent means ± SEM; AL, n=4; WR and WR+Water, n=8. * = p < 0.05 vs. AL, ^ = p < 0.05 vs. WR.