[Protein concentration in the guinea-pig perilymph].

The protein concentration of the guinea pig perilymph was investigated systematically using a micro-modification of the method of Lowry et al. Perilymph of scala vestibuli and of scala tympani was obtained from living animals and immediately post mortem by various methods. In living animals it is especially difficult to obtain samples without blood contamination. Another problem in the obtaining of perilymph from living animals is the contamination of tympanic perilymph samples with cerebrospinal fluid. This contamination diminishes the protein concentration of perilymph to a high degree. When the subarachnoid space is opened suboccipitally before perilymph extraction, there is no significant difference between protein content in tympanic and vestibular perilymph. The mean protein concentration in both cochlea scales is about 150 mg/100 ml. When samples are extracted post mortem from animals perfused intra-arterially, mean values of protein are in the same range. Without perfusion of animals, the mean value of tympanic samples extracted post mortem is significantly higher. Causes of artefacts in perilymph investigations are discussed.