The relationship between vasopressin and endolymphatic hydrops in the guinea pig

Clinical studies have shown that plasma vasopressin level is significantly elevated in patients with Meniere's disease. Other reports indicated that histamine induced a very quick and high elevation of vasopressin level and caused nystagmus in experimentally produced endolymphatic hydrops. We became interested in further investigating the details of this relationship by studying the effect of experimental endolymphatic hydrops and histamine upon plasma vasopressin level in the guinea pig. The results are as follows: 1) Histamine increased the plasma vasopressin level in normal guinea pigs. 2) There was no statistically significant difference in the plasma vasopressin level between the hydrops model and normal guinea pigs. 3) Histamine increased the plasma vasopressin level more in the hydrops model group than in normals. 4) Plasma vasopressin level was elevated in the vertiginous model caused by inner ear anesthesia. Our results support those of clinical investigators who reported that the plasma vasopressin level was elevated more in the Meniere's disease group than any other equilibrium disorder group. It is possible that vasopressin is in someway involved in the development of endolymphatic hydrops.