Lack of hyperbaric O2 effect on blood-brain barrier permeability in conscious rats.

Conscious rats were exposed to 100% O2 at 2.5 ATA for 90 min for up to 10 consecutive days, or to an N2-O2 mixture (PO2 = 0.3 ATA) under the same conditions (control animals). Cerebrovascular permeability to 14C-sucrose in the experimental animals was not altered by hyperbaric O2 exposure when compared to the value in control animals. These results differ with other reports that similar hyperbaric O2 exposure increases cerebrovascular permeability to ferritin and to a protein enzyme.