Abstract
The frog utricle and its nerve were isolated with the anterior and the lateral semicircular canal ampullae in frog Ringer's solution. The utricular otoconia and the otoconial membrane were carefully removed. The cupula of the anterior semicircular canal was removed and was sectioned in half. The halved cupula was stuck into the tip of a glass microelectrode which was mounted on a micromanipulator. The base of the cupula was gently placed on the macula. The micromanipulator allowed sliding motion of the cupula on the macula. The cupula was placed in the center of the medial or lateral part of the macula and was moved toward (striolapetal) or away from (striolafugal) the striola along the axis vertical to the striola. When the medial part of the macula was stimulated, 5 μm of striolapetal cupula movement elicited excitatory nerve discharge. When the lateral part of the macula was stimulated, the striolapetal stimulus likewise induced an excitatory response. These results indicate the presence of physiological polarity on the utricular macula.
