Fig. 5

Osmotherapy does not alter the brain barrier permeability. Na⁺-fluorescein (green fluorescence) was injected into the blood circulation of rats prior to i.p. exposure of isosmolar NaCl (control) or hyperosmolar NaCl (osmotherapy). Naïve rats did not receive Na⁺-fluorescein and were euthanized immediately after anaesthesia induction. a, e Phase contrast images illustrate structures of the brain regions of interest in transmitted white light. Representative images of Na⁺-fluorescein in b–d hippocampus, thalamus, neocortex, and the lateral ventricle (LV) and f–h pineal gland (positive control) of naïve rats, control rats, and osmotherapy-treated rats, n = 3. Scale bar = 500 μm