Morphological Study of the Effect of Intraduodenally Administered Adenosine Triphosphate on the Peripheral Vascular System of the Inner Ear

Abstract

Measurement of maximum and minimum diameter of the superficial blood vessels was performed to clarify the effect of intraduodenally administered ATP on the vascular system of the inner ear. ATP was given to 20 guinea pigs intraduodenally at dose of 30, 100, 300 and 500mg/kg respectively.
Physiological saline solution was given to 5 control animals. The animals were sacrificed and decapitated 15, 30, 60 and 90 minutes after the ATP administration.
Benzidine reaction was made on the formalin fixed cochlea and vestibule to demonstrate the configuration of the blood vessels. The measurement of the blood vessels was conducted on the photomicrographs at the same magnification.
The following results were obtained.
1) The increase in the diameter of the blood vessels was observed in radiating arterioles, suprastrial capillaries and stria vascularis in every turn of the cochlea and in capillary network of the ampullar cristae as well as maculae of the vestibulum in the guinea pigs.
2) The increase in the vascular diameter showed dose dependency, and began to appear at dose of 100mg/kg and became maximum at dose of 500mg/kg.
3) The increase in the vascular diameter was most prominent 15 minutes after the administration of ATP at dose of 500mg/kg and then became decreased gradually to normal value 90 minutes later.
4) These findings suggest that the effect of ATP on the vascular diameter may persist longer in intraduodenal administration than intraperitoneal administration.