D.C. Potentials in the Semi-Circular Canal of thex Pigeon

Abstract

Membranous lateral semi-circular canals of pigeons were explored for measurement of D.C. potential of the endolymphatic fluid. Measurements were made relative to the perilumphatic fluid in the immediate vicinity of the exploring electrode. Explorations were made with both metal micro-electrodes and capillary micropipettes filled with 3 molar KC1. Both types of electrodes gave equivalent recordings of the D.C. potential inside the semi-circular canals. In the ma-ojrity of experiments the membranous canals were opened by incision and the electrodes inserted under visual control. The D.C. potential recorded was consistently high (+ 25 to +28,3 mV). In two experi-mens where the canal wall was penetrated by the micro-electrodes the potentials recorded were low (+ 1 to +2 mV). These findings are discussed.