STUDIES ON CHOLINESTERASE OF LABYRINTHINE AND SPINAL FLUID

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Part I In spite of the recent development of the chemical substance theory on nerve impulse, very few biochemical investigations have been reported on the cochlear response.The author studied the Cholinesterase (ChE) activity of the labyrinthine fluid of guinea-pigs by Conway's microdiffusion analysis.The results obtained were as follows, 1. ChE in the labyrinthine fluid, both that in endolymph and perilymph, was specific Choli-nesterase.2. ChE activity of endolymph was about 4.36 times as much as that of perilymph. Free acetic acid produced from acetylcholine by 1mg endolymph in 40minutes at 38° was 0.0183mg% and by 1mg perilymph, 0.0042mg%.3. The injection of 2% Quinine hydrochloride solution (0.05gr per kg.) decreased gradually the ChE activity of endolymph and perilymph in parallel, but the diminution was slow and small in comparison with other cases.4. The injection of Dihydrostreptomycin (0.4g per kg) decreased the ChE activity more remarka-bly and earlier than the case of Quinine. The diminution of ChE activity of perilymph was more remarkable than that of endolymph.5. The sound stimulation (3000 cps 90db) for 60 hours diminished markedly the ChE activity of labyrinthine fluid and that of endolymph as if inhibited completely.Without stimulation for 7 days after 60 hours stimulation, the ChE activity of endolymph was recovered remarkably, but that of perilymph still remained low.In case of the experiment of repeated 12 hours stimulation and 7 day nonstimuration, the dimi-nution of ChE activity of labyrinthine fluid was slight.Part II The author carried out the clinical experiments on the ChE activity of spinal fluid by Hesterin's method with Beckman's spectrophotometer.The results obtained were as follows.1. Normal ChE activity was 0.175±0.006 ElogIo/I in equilibrium at range λ500mμ, the upper limit was 0.200, and the lower limit was 0.140.2. In 11 cases of conductive deafness, the ChE activities were normal or slightly below normal value except 2 cases of otitis media exsudativa acuta (0.200, 0.210).3. In 19 cases of nerve deafness, a considerable diminution of ChE activity was observed except 2 cases. Especially, in deafness due to detonation, sudden, traumatic, streptomycin, Menier's syndro-me, following to cerebral abscess, Congenital deafmutism, the ChE activity decreased remarkably.Two cases of Cholesteatoma-deafness and nerve deafness with central retinitis showed normal value.