Figure 4.

Beneficial effect of nitric oxide [NO] donor dipropylenetriamine NONOate (DPTA-NO) treatment on preventing vasoconstriction is more robust in smaller pial vessels. Arterioles and venules with diameters smaller than 36 μm (A, C) do not constrict during Plasmodium berghei ANKA (PbA) infection in DPTA-NO–treated mice, whereas those with diameter larger than 36 μm (B, D) showed a mean 11% decrease in diameter on day 6 of infection. Notably, PbA-infected mice treated with saline showed constriction in vessels of all sizes and, in those larger than 36 μm, the decrease in diameter was more severe (19%–24%) than in DPTA-NO–treated mice. Number of vessels analyzed: arterioles <36 μm: 20; arterioles >36 μm: 31; venules <36 μm: 65; venules >36 μm: 63. *: P < .05 compared with baseline (day 0). Statistical analysis was performed by 1-way analysis of variance (ANOVA) for nonparametric repeated measurements, and post hoc analyses to baseline were performed using Bonferroni test. Data are from 3 experiments.