[The effects of two and five percent aqueous phenol on the cat tibial nerve in situ--the local anesthetic-like effect of aqueous phenol].
Phenol is well known as a neurolytic agent because of its denaturing property on protein, but many pain clinicians recognized that it has transient nerve blocking effect like local anesthetics in some cases. This investigation was planned to understand the local anesthetic like effect of phenol with the cat tibial nerve model, while its blood flow was kept intact. The tibial nerve was stimulated electrically every one second, and the compound action potentials of its A-fibers were recorded with an oscilloscope for two hours. Physiological saline solution (PSS), 2% lidocaine and 2% and 5% aqueous phenol were injected into the nerve fibers through a glass capillary tube. In the case of PSS, no remarkable change was recognized during the experiment. The action potentials were depressed to 26.5% of control value 10 minutes after injection in 2% lidocaine group and returned to control levels at the end of observation. In almost all cases of 5% aqueous phenol group the action potentials vanished soon after injection. Some interesting phenomena, the biphasic depression of the action potentials, were observed in 2% aqueous phenol group. The first depression was recognized soon after injection of 2% aqueous phenol, which was faster than that with the 2% lidocaine. After the transient recovery of the action potential, the second depression appeared after thirty minutes. This delayed depression was considered to be due to circulatory damage of the nerve fibers by phenol.
Department of Anesthesiology, Juntendo University, Izu-Nagaoka Hospital, Shizuoka.
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Okazaki
D000779:Anesthetics, Local; D000818:Animals; D002415:Cats; D005260:Female; D008297:Male; D019800:Phenol; D010636:Phenols / Q000494:pharmacology*; D013979:Tibial Nerve / Q000187:drug effects*; D014867:Water
D000779:Anesthetics, Local; D010636:Phenols; D014867:Water; D019800:Phenol