Figure 1.

Pre-stroke ISO aggravated ischemic brain damage, which could be reversed by rhANP. (a) Treatment schedule. Mice were single- or pair-housed for 14 days before MCAO or sham operation. Recombinant human ANP (rhANP; 0.1 mg/kg, 0.5 mg/kg, 1.0 µg/kg) or 0.9% saline was intravenously injected into mice on Day 1 after MCAO. Natriuretic peptide receptor A selective antagonist A71915 (0.5 mg/g) or 0.9% saline was intraperitoneally injected into mice on Day 0 (right after MCAO surgery), Day 1 and Day 2 post-MCAO for mice tested on Day 3 after MCAO. Serum, brain and lung tissues were collected on Day 1 or Day 3 post-MCAO for analysis. Behavioral tests were conducted on Day 1 or Day 3 post-MCAO. (b, c) Diagram indicating the infarct area and peri-infarct area. (d) Infarct volumes were calculated as the percentage of infarct volume to whole brain. (e) Serum concentration of ANP. (f) Neurological deficit score. (g) Total beam breaks in the open field test represent spontaneous locomotor activity. (h) The use of the contralateral paw in the cylinder test was determined by the percentage of left/total and (i) Cerebral MPO activity. Data are presented as individual values plus means ± SDs (n = 7–11/group). Comparisons were determined by one-way ANOVA followed by post hoc Newman–Keuls multiple comparison tests. N.S., not significant, *P < 0.05, **P < 0.01, ***P < 0.001. ISO, isolated housing; MCAO, middle cerebral artery occlusion; PH, pair housing; rhANP, recombinant human atrial natriuretic peptide.