Figure 5.

The ischemia-tolerant state is characterized by lower baseline CBF and energy imbalance in NPA-preconditioned animals. (A) Average CBF maps from controls (Con) and NPA-preconditioned (NPA) animals 3 days after saline or NPA treatment without the induction of experimental stroke. Lower panel: voxel-wise statistics of CBF values between groups indicating voxels with significantly lower CBF in NPA animals in pink, overlaid onto anatomic (T2w) images. There is a global CBF reduction 3 days after NPA treatment compared with controls. (B) Comparison of whole-brain CBF values between groups with and without CO₂ challenge. Although baseline CBF is lower in NPA animals, CBF increases to a similar extent after application of CO₂, which indicates that vasoreactivity is preserved after NPA treatment. (C) Levels of the brain metabolites ATP, AMP, and ECP 3 days after NPA preconditioning or sham treatment. There is significantly more AMP and a lower ECP in brains of the NPA group. AMP, adenosine monophosphate; ATP, adenosine triphosphate; CBF, cerebral blood flow; ECP, energy charge potential; NPA, 3-nitropropionic acid.