The effect of vasopressin upon the cochlear potentials in the guinea pig

The change in the EP, CM, SP and AP during perilymphatic perfusion of vasopressin (antidiuretic hormone) was examined in the guinea pig. The EP was recorded with a microelectrode through the spiral ligament of the second turn. The CM, SP and AP were measured with the differential electrodes in the basal turn. The perfusion of vasopressin at concentration of more than 10(-5)M produced a reversible decrease in the EP. The extent of the EP decline was dependent upon the concentration of vasopressin. Abolition of the effect of vasopressin upon the EP by the resumption of respiration after transient asphyxia was observed. During the perfusion of vasopressin, the CM and AP decreased, while the negative component of the SP increased. The mechanism causing the effect of vasopressin upon the cochlear potentials is discussed.