EFFECT OF L-ASPARTATE AND OXALOACETIC ACID ON COCHLEAR POTENTIALS IN GUINEA PIG
L—天冬氨酸和草酰乙酸对豚鼠耳蜗电位的影响

The effects of L-Aspartate and Oxaloacetic acid on cochlear potentials of guinea pig were investigated with perfusin and electrophysiological technique. The control solution were artificial perilymph solution(Iliott' s solution)and the experimental solution were the 20mM L-Aspartate ,25mM L-Aspertate, or 10mM Oxaloacetic acid respectively. All the experimental solution were perfused through the scala tympani of guinea pig in order to compare with control solution. The perfusion solution was pushed by electrical micropump. The click-evoked CM and APN, were recorded during these perfusion and controlled routines with microcomputer(KDS-I).In these tests perfusions with 20 mM L - Aspartate produced depression of APNI 49% , P<0.01.In these tests perfusions with 25 mM L-Aspartate also decreased the amplititude of APNI 36%.The Both concentrations 20 mM L-Asp and 25mM L - Asp without effect on CM.The experiments perfusions with lOmM Oxaloacetic acid had no effect on APNI and CM.The effect of L-Aspartate in cochlea of guinea pig appear to be a potent depolarising agent,and the effect of high concentration of it on postsynaptic membrane was higher degree of depolarization.It is supposed that the L-Aspar-ate may be to cause the change of Calcium and indirectly effect on the release of transmitter.