Because inner ear organs are interconnected through the endolymph and surrounding endolymphatic membrane, the patients with sudden sensorineural hearing loss (SSNHL) often complain of vertigo. In this study, we report a patient with SSNHL accompanied by persistent positional vertigo, and serial findings of head-roll tests are described. At acute stage, head-roll test showed persistent geotropic direction-changing positional nystagmus (DCPN), which led to a diagnosis of SSNHL and ipsilateral light cupula. Although vertigo symptom gradually improved, positional vertigo lasted for more than 3 weeks. At this chronic stage, persistent apogeotropic DCPN was observed in a head roll test, which led to a diagnosis of the heavy cupula. Although the mechanism for the conversion of nystagmus direction from geotropic to apogeotropic persistent DCPN is unclear, the change of specific gravity of the endolymph might be one of the plausible hypothetical explanations.
Diagnosis ; Ear, Inner ; Endolymph ; Head ; Hearing Loss, Sensorineural* ; Humans ; Membranes ; Nystagmus, Physiologic ; Specific Gravity ; Vertigo*

BACKGROUND AND OBJECTIVES: Strial marginal cells are known to secrete K(+) into endolymph. Slowly activating, voltagede-pendent K(+) channels (I(sK) channels) have been identified in the apical membrane of these cells. Although antidiuretic hormone (vasopressin) has been known to play an important role in the various tissues, its physiological and phamacological roles in the inner ear are still unknown. The purpose of this study is to to investigate the hypothesis that vasopressin increases apical K(+) secretion. MATERIALS AND METHODS: On-cell macro-patch recordings were made on the apical membrane of strial marginal cells dissected from neonate rat. The effect of vasopressin was compared to the one of raising the bath K(+) concentration. RESULTS: We observed I(sK) channels in 21 patches (9%) of 235 high resistance seals. When the pipette contained NaCl-pipette solution, raising the bath K(+) concentration from 3.6 mM to 25 mM led to a statistically significant increase in apical outward K(+) current from 0.44+/-0.04 pA to 3.31+/-0.40 pA (n=10). When the bath K(+) concentration was returned to 3.6 mM, the outward current declined to 0.45+/-0.04 pA, which was not statistically different from the original level. Arginine vasopressin (AVP, 10-7 M) increased apical current from 0.43+/-0.04 pA to 2.20+/-0.30 pA (n=10). The current stimulated by elevated AVP was carried by the apical I(sK) channel. CONCLUSION: Our results demonstrate that AVP receptor is present in marginal cells and that AVP increases transepithelial K(+) secretion by activation of I(sK) channel in neonate rat.
Animals ; Arginine Vasopressin ; Baths ; Ear, Inner ; Endolymph ; Humans ; Infant, Newborn* ; Membranes ; Rats ; Vasopressins

BACKGROUND AND OBJECTIVES: The plasma stress-related hormonal [cortisol, growth hormone, prolactin, antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH)] levels have been reported to be elevated in sudden sensorineural hearing loss (SSNHL) patients. However, little is known regarding the mechanisms related with the elevation of stress-related hormonal levels in SSNHL. Therefore, we measured the level of plasma stress-related hormones in SSNHL patients and in normal persons to demonstrate the association between the stress-related hormones and SSNHL. SUBJECTS AND METHOD: Stress-related hormonal levels were measured from 68 patients who were diagnosed with SSNHL. These values were compared with the stress-related hormonal levels of 24 healthy control subjects. RESULTS: The plasma ADH levels was significantly higher in SSNHL group compared with that in their normal control group, as shown by their respective values, 4.46 [95% confidence interval (CI): 3.80-5.24 pg/mL] and 3.05 (95% CI: 2.34-3.98 pg/mL). The values for plasma cortisol, growth hormone, and ACTH levels whose values were 2.07 (95% CI: 1.65-2.61 microg/L), 0.20 (95% CI: 0.14-0.29 microg/L), and 12.79 (95% CI: 11.16-14.66 pg/mL), respectively, were significantly lower in the SSNHL group than those in the normal control group whose values were 7.86 (95% CI: 5.33-5.24 microg/L), 0.61 (95% CI: 0.36-1.04 microg/L), 18.48 (95% CI: 14.99-22.78 pg/mL), respectively. But there was no significant difference in prolactin between the two groups. CONCLUSION: This study demonstrates a possible role of stress-related hormones in the pathogenesis of SSNHL. However, only ADH level was higher than the control group. Furthermore, ACTH, growth hormone and cortisol levels were lower than the control groups. This means ADH, growth hormone, cortisol, ACTH levels are related with SSNHL. However, the impact of this hormone on the inner ear and endolymph homeostasis is still unknown. Further investigation is necessary to identify the action mechanism of these hormones in the inner ear.
Adrenocorticotropic Hormone ; Ear, Inner ; Endolymph ; Growth Hormone ; Hearing Loss, Sensorineural* ; Homeostasis ; Humans ; Hydrocortisone ; Plasma ; Prolactin

Benign paroxysmal positional vertigo (BPPV) is a common inner ear cause of vertigo, most of which can be treated by particle repositioning maneuver (PRM). However, in rare cases, positional vertigo could persist or frequently recur after several PRM. In these intractable cases, surgical treatments including singular neurectomy and semicircular canal occlusion have been used. Posterior semicircular canal occlusion has some advantages over singular neurectomy in hearing preservation and feasible surgical technique. Also free-floating endolymph particles causing intractable BPPV are known to occur in about 20% of the cases during canal occlusion surgery. Nevertheless, to the best of our knowledge, there has not been any report on the identification of those particles in the Korean literature. In this paper, we report a case of free-floating endolymph particle found during transmastoid posterior semicircular canal occlusion for intractable posterior canal BPPV.
Benign Paroxysmal Positional Vertigo* ; Ear, Inner ; Endolymph* ; Hearing ; Semicircular Canals* ; Vertigo

OBJECTIVETo attempt to visualize the endolymph in patients with Meniere's disease by applying non-invasive intratympanic gadolinium through eustachian tube and three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI).

METHODSWith a 3 Tesla magnetic resonance imaging (MRI) unit, 3D-FLAIR imaging was performed 24 hours after intratympanic gadolinium through eustachian tube in two patients with medically active and intractable Meniere's disease. Pure tone test and tympanometry were performed 24 hours before and after the administration of gadolinium.

RESULTSThe gadolinium appeared in almost all parts of the perilymph inside the inner ear; moreover, the border between the perilymph and the endolymph was visible so endolymphatic space was clearly shown on 3D-FLAIR. No change in pure tone test and tympanometry was noted.

CONCLUSIONS3D-FLAIR MRI with intratympanic gadolinium through eustachian tube can clearly reveal the visualization of endolymph in patients with Meniere's disease. Intratympanic gadolinium therapy through eustachian tube is a safe and effective.

Adult ; Endolymph ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; Male ; Meniere Disease ; diagnostic imaging ; Middle Aged ; Radiography

In order to know the effects of caloric stimulation on neuronal firing in medial vestibular nuclei (MVN) by middle ear irrigation, the middle ear was irrigated with ice (4 degrees C), hot (44 degrees C), and warm (37 degrees C) water, and the firing rate of MVN neuron was extracellularly recorded. The results showed that the firing rate of MVN neuron was changed by caloric stimulation, and the majority of MVN neurons showed excitation by irrigation with hot water and inhibition by ice water (type A). The neuronal firing was recovered immediately after the cessation of the stimulation. I It was concluded that the neuronal firing rate in MVN was changed by caloric stimulation in middle ear cavity. The response was different in various neurons.
Cold ; Ear, Middle ; Electrophysiology ; Endolymph/physiology ; Heat ; Irrigation ; Neurons/classification ; Neurons/physiology ; Rats, Wistar ; Vestibular Nerve/*physiology ; Vestibular Nuclei/*physiology

Pendred syndrome is an autosomal recessive condition classically characterized by congenital deafness and goiter, and is the most common cause of hereditary deafness in Korea. It is caused by mutations in the PDS gene (SLC26A4) located in 7q31. The PDS gene encodes a chloride-iodide transport protein called pendrin, which plays a role in the reabsorption of endolymph and the maintenance of the endolymph homeostasis in the inner ear and in the uptake and organification of iodide in the thyroid gland. A mutation in PDS also causes non-syndromic recessive deafness (DFNB4) and therefore securing the diagnosis is important for genetic counseling purposes. The perchlorate discharge test and radiological conformation of the inner ear anomaly are useful diagnostic aids but have limited diagnostic value. However, because PDS mutations are widely distributed along the gene, it consumes too much time and money to perform molecular studies in clinics. We present a case of congenital sensorineural hearing loss with multinodular goiter, which shows definite findings of Pendred syndrome.
Deafness ; Diagnosis ; Ear, Inner ; Endolymph ; Genetic Counseling ; Goiter* ; Hearing Loss, Sensorineural* ; Homeostasis ; Korea ; Thyroid Gland ; Vestibular Aqueduct

Hydrops of the endolymphatic space in the inner ear deteriorates hearing and balance function. This idiopathic syndrome of endolymphatic hydrops is Meniere's disease and is characterized by episodic vertigo, fluctuating hearing loss, tinnitus and ear fullness. For the pathophysiologic mechanisms of the episode, the progression of the hydrops leads to ruptures in the membranes separating endolymph from perilymph, producing a sudden increase in potassium concentration in the perilymph. Recurrent episodes may interfere with routine daily activities and sometimes accompany sudden drop attacks, so called Tumarkin's otolithic crisis, which may lead to serious injuries. Life style modification, low salt diet and prescription of diuretics have been traditionally tried in order to relieve endolymphatic hydrops. Surgical and destructive treatment options are necessary in selected intractable patients depending on the frequency of vertigo, severity of hearing loss and the possibility of bilateral involvement. However, a large proportion of these patients shows a spontaneous cure of vertigo with the aggravation of hearing loss (burnt out stage) over time. The goal of treatment is trying not to make the patient worse than this natural course of disease.
Diet ; Diuretics ; Dizziness ; Ear ; Ear, Inner ; Edema ; Endolymph ; Endolymphatic Hydrops ; Hearing ; Hearing Loss ; Humans ; Life Style ; Membranes ; Meniere Disease ; Otolithic Membrane ; Perilymph ; Potassium ; Prescriptions ; Rupture ; Syncope ; Tinnitus ; Vertigo

BACKGROUND AND OBJECTIVES: Gentamicin, which is known to have potential toxic effect to the inner ear, causes functional disturbance by destroying the inner ear at a concentration above a certain level. The purpose of this study was to identify morphological changes in the endolymphatic sac after gentamicin injection using chick embryo and the degree of changes according to different concentration of gentamicin. MATERIALS AND METHOD: The same breed of chicken (Gallus domesticus) was chosen and artificial growth incubator was used to germinate the eggs. Increasing the concentration of gentamicin at the same rate (10, 20, 30, 40 mg/ml), we injected it into the yolk sac of chicken and observed the morphological changes in the embryonic sac by light microscope. RESULTS: As the concentration of gentamicin increased, the size of the endolymphatic sac increased and the thickness and contour of sac wall changed. Especially, the inner membrane thinned down greatly. CONCLUSION: In this research, we confirmed that endolymphatic sac is affected by gentamicin in proportion to its concentration. Especially, considering that inner membrane epithelial cells play an important role in the absorption of endolymph, we suggest that the ototoxicity of gentamicin causes the disturbance in the absorption of endolymph, which may cause endolymphatic hydrops.
Absorption ; Animals ; Chick Embryo* ; Chickens ; Ear, Inner ; Eggs ; Embryonic Structures ; Endolymph ; Endolymphatic Hydrops ; Endolymphatic Sac* ; Epithelial Cells ; Gentamicins* ; Incubators ; Membranes ; Ovum ; Yolk Sac

BACKGROUND AND OBJECTIVES: The endolymph produced from cochlear lateral wall regulates fluid balance and maintains positive endocochlear potentials. Although many immunohistochemical studies on ion transport enzymes have been reported, their mechanisms are still not completely understood. And there are no reports on the distribution of receptor tyrosine kinases in the cochlear lateral wall of the guinea pig. The purpose of this study is to evaluate the expression of the fibroblast growth factor receptor (FGFR) and transforming growth factor receptor-beta (TGFR-beta, type II) in the lateral wall of the guinea pig cochlea. MATERIALS AND METHODS: We investigated the immunohistochemical localization of the receptor tyrosine kinases (FGFR, TGFR-beta) in the lateral wall of the Preyer's positive, pigmented guinea pig. RESULTS: The results showed that receptor tyrosine kinases were expressed in the cytoplasm of the marginal cells, intermediate cells in the stria vascularis, and type II, III, IV, and V fibrocytes, but not the basal cells and type I fibrocytes, in the lateral wall of the guinea pig. CONCLUSION: The findings suggest that receptor tyrosine kinases are involved in the various ion transports and that they participate in the PLC-IP(3) second messenger system.
Animals ; Cochlea ; Cytoplasm ; Endolymph ; Guinea Pigs* ; Guinea* ; Ion Transport ; Phosphotransferases ; Receptors, Fibroblast Growth Factor ; Second Messenger Systems ; Signal Transduction ; Stria Vascularis ; Transforming Growth Factors ; Tyrosine ; Water-Electrolyte Balance