[Experimental investigation on relationship between autonomic nervous system and internal ear function].

Changes in cochlear microphonics (CM) were observed by the injection f vegetative stimulants into the abdominal cavity, by the application f nicotine to the superior cervical ganglion, and by excision or electric stimulatian of the cervical sympathetic nerve and vagus nerve on guinea-pigs. 1) C. M. is reduced by the injection fatropine and acetylcholine while it is induced at the biginnig and then reduced by the injection fpilocarpine. By the injection fadrenaline, C.M. may be either induced or reduced. according to frequency though variation is slight. By the injection fchlorpromazine, C. M. is either induced or reeuced slightly in some cases, although there are other cases of reduction in C. M. By the application f nicotine to the superior cervical ganglion, C. M. is first reduced and then induced. 2) Atter the excision of the cervical sympathetic nerve, C. M. is first induced and is gradually reduced afterward. Excision of the vagus nerve has little influence on C. M. in some cases, but there are othe cases where C. M. is slightly reduced. 3) Stimulation to the eervical sympathetic nerve reduces C. M., but stimulation tothe vagus nerve has no influence on C. M. 4) Stimulation to the superior cervical ganglion reduces degree of recovery from sound fatigue for C. M. 5) Regulation of internal ear function by autonomic nervous system is likely to be occured by angioneurotic control over the blood flow, and at the seme time by adjustment o the excitability of sensory cells in the internal ear.