Adenylate cyclase activity in the fetal and the early postnatal inner ear of the mouse

Abstract

The adenylate cyclase activity was analyzed in fetal, early postnatal and adult inner ears of the CBA/CBA mouse and also in approximately one month old inner ears from Shaker -1 and Shaker -2 mice. A comparison was made with the maturation of potassium levels in endolymph as investigated with the X-ray energy dispersive technique. Adenylate cyclase activity in the developing normal inner ear shows two significant periods of increases: from the 16th to the 19th gestational day in both the cochlear and vestibular parts of the labyrinth, and from birth to day 6 after birth in the lateral wall tissues of the scala media. During the first period the anatomical boundaries of the secretory epithelia are developing. The postnatal rise in adenylate cyclase activity correlates with the morphological maturation of stria vascularis at the cellular and subcellular levels and the rise in potassium content of endolymph. The rise of enzyme activity in the cochlear during the maturation of endolymph supports a link between adenylate cyclase and the control of inner ear fluids. Adenylate cyclase activity in stria vascularis/spiral ligament of Shaker -1 and Shaker -2 mice were at normal levels and correlated better with the rather normal morphology of the tissues than the abnormal composition of endolymph in these mutants.

Effects of vasopressin on gene expression in rat inner ear

“…Gnas may couple Gprotein coupled receptor binding to AC activation. This result is supported by the previous findings: (1) AC was present in the stria vascularis and semicircular canal epithelium of the inner ear (Ahlstrom et al, 1975;Bagger-Sjoback et al, 1980;Anniko et al, 1981;Mees, 1984;Schacht, 1985;Oudar et al, 1990;Drescher et al, 2000).…”

Cellular localization of adenylate cyclase in the developing and mature inner ear of the mouse

“…contains the highest activity of adenylate cyclase in the cochlea [1. 5,7]. Further, a correlation between the postnatal maturation of the ionic profile of endolymph and increasing strial adenylate cyclase activity was demonstrated biochemically [5].…”

Hyaluronic Acid as a Molecular Filter and Friction-Reducing Lubricant in the Human Inner Ear

“…Similar quantitative differences have been re ported for many enzyme systems responsible for K+-rich and NaMow content of endolymph during both the matu ration of endolymph [25] and at the adult stage [26], The increased concentration of endolymphatic K+ in the base [27] parallels the distribution of stria Na+-K+ ATPase [28] . However, anatomically the stria vascularis increases in thickness and surface area from apex to base.…”