Pyrenebutyric acid as an optical oxygen probe in the intact cerebral cortex.

The application of the fluorochrome pyrenebutyric acid (PBA) as an in vivo quantitative probe for intracellular oxygen tension (iPO2) is reported. PBA is nontoxic, noninvasive, nonconsumptive, and allows optical monitoring of iPO2 on line. Cats were anesthetized with ether and lesioned midcollicularly to produce cerveau isolé preparations with optical monitoring via a compensated microfluorometer. The "normal" iPO2 was determined to be 42.8 /- 8.6 (SD) mmHg. Decrease in cerebral perfusion results in observing a decreased iPO2. This method of monitoring iPO2 was found to overcome drawbacks inherent in the polarographic technique and to posess additional advantages.