Increased macromolecular resonances in the rat cerebral cortex during severe energy failure as detected by 1H nuclear magnetic resonance spectroscopy.

Changes in cerebral macromolecular 1H nuclear magnetic resonance (NMR) spectrum were studied in cortical brain slices in vitro. Aglycaemic hypoxia irreversibly increased various short T2 spectral components at 1.8-0.8 ppm in concordance with energy loss and independent of T1 and T2 relaxation effects. Removal of external calcium (Ca2+e) slightly attenuated the effect. The results suggest NMR-visible reorganisation of intracellular proteins due to hypoxic insult, and show that it may be possible to monitor early cytoplasmic changes due to brain energy depletion by NMR spectroscopy.