Influence of catecholamines on perilymph Po2.

In a previous study, a special rheological model of intra-arterial perfusion was used to examine the existence and effectiveness of vasomotor control of the cochlear vessels in guinea pigs. Catecholamines were injected intra-arterially into this animal model and the changes induced in the cochlear action potentials were examined. In this investigation, we used the same animal model and technique to measure the perilymph Po2 after perfusion of the cochlea with catecholamines. In addition, the effect of drainage of the CSF before infusion was examined. The results indicated that opening the labyrinth allows the escape of CSF through the patent cochlear duct. This may modify the concentration of the substance under study in the perilymph and cause inaccuracies in the data obtained.