The Mutual Independence of the Endolymphatic Potential and the Concentrations of Sodium and Potassium in Endolymph

Brusilow, Saul W.; Gordes, Ellen H.

doi:10.1172/jci107442

Cited by 26 publications

(10 citation statements)

References 14 publications

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“…Fish data included endolymph and perilymph measurements, respectively, from Atlantic cod saccule and cranial cavity, basking shark saccule, canal, and cranial cavity, Cottus scorpius saccule and cranial cavity, Salmo irideus saccule and cranial cavity, skate saccule and cranial cavity (Enger, 1964); Atlantic cod canal and cranial cavity, burbot canal and cranial cavity, Greenland shark canal and bony labyrinth, rock grenedier canal and cranial cavity, grey sole canal (Fänge et al, 1972); shark canal (Garvin et al, 1988); skate canal and fenestra ovalis (Peterson, 1978); and toadfish utricle, saccule and perilymphatic cavity (present study). Other data included measurements from cat scala tympani and scala media, lizard scala vestibuli and scala media (Peterson, 1978); cat scala tympani and scala media, endolymphatic sac (Silverstein and Schuknecht, 1966); cat scala tympani and scala media, guinea pig scala tympani and utricle (Citron et al, 1956); cat scala tympani and utricle, dog scala tympani (Maggio, 1966b); cat scala tympani and scala media (Davies, 1968); cat scala vestibuli, scala tympani, scala media, and utricle (Makimoto and Silverstein, 1974); dog scala tympani and scala media, guinea pig scala tympani and scala media (Brusilow and Gordes, 1973); gerbil utricle and bony labyrinth (Marcus and Marcus, 1987); guinea pig scala tympani and utricle (Smith et al, 1954); guinea pig scala tympani and scala media (Johnstone et al, 1963); pigeon scala vestibuli and scala media (Sauer et al, 1999); rat scala vestubuli, scala tympani, and scala media (Bosher and Warren, 1968); bullfrog saccule (Corey and Hudspeth, 1983a); and turtle endolymphatic cochlea (Crawford et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

Ionic Composition of Endolymph and Perilymph in the Inner Ear of the Oyster Toadfish,Opsanus tau

Ghanem

Breneman

Rabbitt

et al. 2008

The Biological Bulletin

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Abstract. The concentrations of free Na ϩ , K ϩ , Ca 2ϩ , and Cl -in endolymph and perilymph from the inner ear of the oyster toadfish, Opsanus tau, were measured in vivo using double-barreled ion-selective electrodes. Perilymph concentrations were similar to those measured in other species, while endolymph concentrations were similar to those measured previously in elasmobranch fish, though significantly different from concentrations reported in mammals. Perilymph concentrations (mean Ϯ std. dev.) were as follows: Na ϩ

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Section: Discussionmentioning

confidence: 99%

Ionic Composition of Endolymph and Perilymph in the Inner Ear of the Oyster Toadfish,Opsanus tau

Ghanem

Breneman

Rabbitt

et al. 2008

The Biological Bulletin

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“…They were deprived of food but not water for [11][12][13][14][15][16][17][18] hr prior to study. They were anesthetized with an intraperitoneal injection of DIAL with urethane (0.9 g/kg of body weight).…”

Section: Methodsmentioning

confidence: 99%

“…After a ventromedial incision in the neck and removal of the posterior portion of the mandible, the auditory bulla was exposed and removed. The basilar membrane of the first turn of the cochlea was exposed after removal of the round window membrane (15).…”

Section: Methodsmentioning

confidence: 99%

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Effects of cholera toxin on cochlear endolymph production: model for endolymphatic hydrops.

Feldman¹,

Brusilow²

1976

Proc. Natl. Acad. Sci. U.S.A.

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To evaluate a possible role for adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.11 and adenosine 3':5'-cyclic monophosphate in the secretion of endolymph, we studied the effect of an intra-scala media injection of purified cholera toxin (an adenylate cyclase stimulant) on cochlear endolymph volume, endolymphatic potential, and endolymphatic, Na and K concentrations. The endolymph volumes of animals injected with either deactivated cholera toxin or 0.15 M KCI were the same, and there was no difference in the endolymphatic potential in the control and treated groups. The increased endo-ymph volume suggests the resence of an active adenylate cyclase system in the scala media which may play a role in the formation of endolymph. Adenosine 3':5'-cyclic monophosphate (cyclic AMP) has been shown to be the intracellular mediator of salt and water absorption in the toad urinary bladder (1) and renal collecting tubules (2, 3). It has also been shown to enhance secretion from the intestinal epithelium (4), salivary glands (5), pancreas (6), and renal tubule (7). Cyclic AMP production has been stimulated by biogenic amines, many hormones (8), and purified cholera exotoxin (9, 10). By a direct stimulatory action on adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1], cholera toxin produces secretion of isotonic fluid by the gut (11), the action being mimicked by agents that increase cellular cyclic AMP concentrations. Although the molecular mechanisms for fluid absorption and secretion are not known, it has been demonstrated that cyclic AMP can alter membrane permeability (2, 12) as well as membrane electrolyte secretion (4, 7).The stria vascularis is assumed to be the epithelia membrane responsible for the maintenance of the endolymphatic potential (EP) and endolymph secretion into the scala media of the cochlea (13,14).The present study was performed to demonstrate the presence and possible role of cyclic AMP in the stria vascularis by stimulating intracochlear adenylate cyclase with purified cholera toxin. The toxin had a significant effect on endolymph production, although it did not alter either endolymphatic potential or electrolyte composition. MATERIALS AND METHODSExperiments were performed on guinea pigs (Hartley strain) weighing between 150 and 300 g that were allowed free access to food and water. They were deprived of food but not water for 11-18 hr prior to study. They were anesthetized with an intraperitoneal injection of DIAL with urethane (0.9 g/kg of body weight). A tracheostomy was performed and artificial ventilation was maintained by positive pressure ventilation. The animals were placed on a warmer and the electrocardiogram was constantly monitored. After a ventromedial incision in the neck and removal of the posterior portion of the mandible, the auditory bulla was exposed and removed. The basilar membrane of the first turn of the cochlea was exposed after removal of the round window membrane (15).An initial endolymphatic potential measurement was made using a si...

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“…3ecause cochlear endolymph contains high K+ and low Na+ concentrations (6), an iontransporting system has been implicated in the cochlear membranous lateral wall involving adenosine triphosphatase (7) and carbonic anhydrase (5,8). Although the physiological significance of the high concentration of endolymphatic K+ is still unclear (9), the high K+ is likely to be necessary for normal functioning of the mammalian inner ear. As a first step in investigations of the molecular properties and possible role of carbonic anhydrase in the cochlea, I have studied the distribution of the activity of this enzyme in cochlear fractions of the guinea pig and purified a major soluble form of carbonic anhydrase from cochlear membranous lateral wall.…”

mentioning

confidence: 99%

Purification of a carbonic anhydrase from the inner ear of the guinea pig.

Drescher¹

1977

Proc. Natl. Acad. Sci. U.S.A.

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A 'soluble carbonic anhydrase (carbonate hydro-lyase, Eq 4.2.1.1) has been purified to homogeneity from the membranods lateral wall (stria vascularis, spiral ligament, spiral prominence, and outer sulcus) of the guinea-pig inner ear. About 1% of the protein of the membranous lateral wall is carbonic anhydrase. The specific activity of the enzyme in hoinogenates of the lateral wall is 1.6-1.8 times that of whole blood; for homogenates of the components, stria vascularis and the fraction containing the spiral ligament, the specific activities are 0.9 and 2.0 times the specific activity of whole blood, MATERIALS AND METHODS All chemicals used in these studies were of reagent grade or better. 5-Dimethylaminonaphthalene-l-sulfonamide (DNSA) was from K & K Fine Chemicals, Plainview, N.Y., and the chromatographic resins were from Bio-Rad, Richmond, Calif.The animals were normal, colored guinea pigs of both sexes weighing 160-320 g. Animals were decapitated and their blood was collected in containers on ice. Blood from each animal was diluted 'oo or 6oo in deionized water at 4°. Temporal bones were dissected with surgical scissors and placed on ice within 1 min of death. Intact cochleas were then removed and immersed in a dissecting medium of 10 mM Tris-sulfate, 100 mM Na2SO4, pH 7.4 at 1-2°. Dissections were performed in the medium using a dissecting microscope. A sample of bony shell that covered the fourth turn was chipped away with a forceps and the remaining cochlear bone was removed, exposing the intact spiral of the membranous lateral wall, which was unwound (10). The basilar and tectorial membranes, the remaining cochlear epithelium, and a small amount of bone, comprising the "organ-of-Corti fraction," were scraped from the bony spiral with a finely pointed forceps. The auditory nerve was dissected from the modiolus to the internal auditory meatus. In separate experiments, the medulla oblongata was exposed and the left temporal bone was removed after the cranial nerves entering it were cut. Then the whole cochlear nucleus was dissected with a small spatula. All dissected tissues were rinsed in cold medium, placed in ground-glass homogenizers (0.2-ml nominal capacity; Kontes Glass Co., Vineland, N.J.), homogenized in 50 AM of deionized water for 15-30 min on ice, and diluted with water to the following volumes: 30 ,Ml/sample of cochlear bone containing 16 ,ug of protein, 2 ml/cochlear nucleus, 300 Ml/auditory nerve, 70Al/organ-ofCorti fraction from one cochlea, and 220 Al/membranous lateral wall from one cochlea. Each fraction, except cochlear nucleus and whole blood, contained tissue samples from more than one animal. Each experiment (Table 1) consisted of the analysis of one fraction. The average number of animals used per fraction can be determined from Table 1.Lyophilized tissue was used in experiments where the stria vascularis was separated from the spiral ligament fraction, because the use of fresh tissue caused loss of carbonic anhydrase into the medium when the fractions were separated. Fresh coc...

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The Mutual Independence of the Endolymphatic Potential and the Concentrations of Sodium and Potassium in Endolymph

Cited by 26 publications

References 14 publications

Ionic Composition of Endolymph and Perilymph in the Inner Ear of the Oyster Toadfish,Opsanus tau

Ionic Composition of Endolymph and Perilymph in the Inner Ear of the Oyster Toadfish,Opsanus tau

Effects of cholera toxin on cochlear endolymph production: model for endolymphatic hydrops.

Purification of a carbonic anhydrase from the inner ear of the guinea pig.

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