Changing cation levels (Mg2+, Ca2+, Na+) alters the release of glutamate, GABA and other substances from the guinea pig cochlea

Bobbin, Richard P.; Ceasar, Gail; Fallon, Maureen

doi:10.1016/0378-5955(91)90143-w

Cited by 15 publications

(8 citation statements)

References 40 publications

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“…In the case of arginine and histidine this may be via reductive adsorption of their extra amine groups R-CH 2 -NH 2 r R-CH=NH ϩ 2H ϩ ϩ 2e [5] R-CH=NH r R-CϵN ϩ 2H ϩ ϩ 2e [6] Splitting of the carbon nitrogen bond may lead to the formation of aldehydes In our experiments basic amino acids were found to adsorb to a greater degree at the electrode surface and to yield greater oxidation currents.…”

Section: Discussionmentioning

confidence: 62%

Voltammetry of Platinum in Artificial Perilymph Solution

Hibbert

Weitzner

Carter

2001

J. Electrochem. Soc.

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Mammalian cochlea perilymph contains amino acids and protein which have a major effect on the electrochemistry of an implanted auditory prosthesis. Cyclic voltammetry in an artificial perilymph solution shows that many amino acids adsorb at the platinum electrode diminishing oxidation of the metal, and also blocking hydrogen evolution. At anodic potentials > 900 mV vs. silver/silver chloride they are oxidized leaving adsorbed oxidation products. The sulfur-containing amino acids cysteine and methionine have the greatest effects. Protein (human serum albumen, HSA) has a similar but smaller effect. A solution containing HSA (2 mg mL Ϫ1 ), phenylalanine (175 M), glycine (396 M), and proline (40 M) in phosphate buffered saline is proposed as a suitable artificial perilymph solution having similar electrochemical and adsorption properties to perilymph. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.237.29.138 Downloaded on 2015-03-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.237.29.138 Downloaded on 2015-03-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.237.29.138 Downloaded on 2015-03-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.237.29.138 Downloaded on 2015-03-08 to IP

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Section: Discussionmentioning

confidence: 62%

Voltammetry of Platinum in Artificial Perilymph Solution

Hibbert

Weitzner

Carter

2001

J. Electrochem. Soc.

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“…The strongest evidence supporting this hypothesis is the expression of f unctional glutamate receptors by SGNs and their localization postsynaptic of the hair cell synapse (Bledsoe et al, 1981;Puel et al, 1991a,b;Ryan et al, 1991;Safieddine and Eybalin, 1992b;Kuriyama et al, 1994;Niedzielski and Wenthold, 1995). Although glutamate is present in hair cells, and its release from hair cells is stimulated by K ϩ in a Ca 2ϩ -dependent manner (Jenisson et al, 1985;Bobbin et al, 1990Bobbin et al, , 1991Kataoka and Ohmori, 1994; for review, see Eybalin, 1993), some studies suggest that a novel excitatory amino acid may be f unctioning at this synapse (Sewell and Morz, 1987).…”

Section: Abstract: Cochlea; Vestibular End Organ; Hair Cells; Spiralmentioning

confidence: 98%

The Glutamate Receptor Subunit δ1 Is Highly Expressed in Hair Cells of the Auditory and Vestibular Systems

Safieddine

Wenthold

1997

J. Neurosci.

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In the inner ear, fast excitatory synaptic transmission is mediated by ionotropic glutamate receptors, including AMPA, kainate, and NMDA receptors. The recently identified ␦1 and ␦2 glutamate receptors share low homology with the other three types, and no clear response or ligand binding has been obtained from cells transfected with ␦ alone or in combination with other ionotropic receptors. Studies of mice lacking expression of ␦2 show that this subunit plays a crucial role in plasticity of cerebellar glutamatergic synapses. In addition, these mice show a deficit in vestibular compensation. These findings and the nature of glutamatergic synapses between vestibulocochlear hair cells and primary afferent dendrites suggest that ␦ receptors may be functionally important in the inner ear and prompted us to investigate the expression of ␦ receptors in the cochlea and peripheral vestibular system. Reverse transcription and DNA amplification by PCR combined with immunocytochemistry and in situ hybridization were used. Our results show that the expression of ␦1 in the organ of Corti is intense and restricted to the inner hair cells, whereas ␦1 is expressed in all spiral ganglion neurons as well as in their satellite glial cells. In the vestibular end organ, ␦1 was highly expressed in both hair cell types and also was expressed in the vestibular ganglion neurons. The prominent expression of ␦1 in inner hair cells and in type I and type II vestibular hair cells suggests a functional role in hair cell neurotransmission. Key words: cochlea; vestibular end organ; hair cells; spiral ganglion neurons; PCR; in situ hybridization; Western blot; immunocytochemistryAuditory and vestibular stimuli are detected by hair cells in the inner ear and are transmitted to the brain by way of the auditory and vestibular nerves. Of the two types of hair cells found in the organ of Corti, inner hair cells (IHC s) and outer hair cells (OHC s), IHC s are the primary transducers of sensory information. IHC s form chemical synapses with dendrites of type I spiral ganglion neurons (SGNs) that constitute 90 -95% of the SGNs. OHC s synapse on the remaining type II SGNs (Spoendlin, 1972;Berglund and Ryugo, 1987). The vestibular epithelium contains two types of sensory hair cells. T ype I cells (V HCI) are flaskshaped and surrounded by an afferent nerve caly x, whereas type

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“…Membrane depolarization and Ca 2+ in the extracellular medium are required for neurotransmitter release (Jenisson et al . 1985;Bobbin et al . 1991;Parson et al .…”

Section: Introductionmentioning

confidence: 99%

“…As in the CNS, synaptic transmission at IHC-afferent dendrites is chemically mediated and has many properties typical of fast synaptic transmission in the CNS. Membrane depolarization and Ca 2ϩ in the extracellular medium are required for neurotransmitter release (Jenisson et al, 1985;Bobbin et al, 1991;Parson et al, 1994;. The synaptic vesicles are morphologically similar to those in the CNS, and cochlear hair cell synapses have an active zone with a patch of synaptic membrane where synaptic vesicles cluster or are docked.…”

Section: Introductionmentioning

confidence: 99%

SNARE complex at the ribbon synapses of cochlear hair cells: analysis of synaptic vesicle‐ and synaptic membrane‐associated proteins

Safieddine

Wenthold

1999

Eur J of Neuroscience

162

169

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Neurotransmitters are released via exocytosis of synaptic vesicles involving a fusion complex consisting of a set of highly conserved proteins, which form a multiprotein complex resulting in the docking of synaptic vesicles at the site of release. There are three major differences between cochlear hair cell synapses and CNS synapses: (i) hair cells have a specialized structure, the synaptic ribbon, to which synaptic vesicles are attached; (ii) hair cells can maintain high and sustained release of neurotransmitter; and (iii) hair cells lack synaptophysin and synapsin. These differences suggest that an unconventional mechanism of neurotransmitter release may be involved at ribbon synapses. In this study we used different and complementary approaches to determine whether or not ribbon-containing hair cells of the cochlea express any component of the core fusion complex found in conventional synapses. Syntaxin 1, the synaptic membrane synaptosome-associated protein (SNAP)-25 and vesicle-associated membrane protein (VAMP or synaptobrevin) were found to be present in the organ of Corti of both rat and guinea-pig, as shown by reverse transcription polymerase chain reaction and Western blotting. In situ hybridization and immunocytochemistry showed mRNA and protein expression, respectively, in both inner and outer hair cells. Synaptotagmins I and II, generally considered to play major roles in neurotransmitter release at central synapses, were not detected in the organ of Corti.

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Changing cation levels (Mg2+, Ca2+, Na+) alters the release of glutamate, GABA and other substances from the guinea pig cochlea

Cited by 15 publications

References 40 publications

Voltammetry of Platinum in Artificial Perilymph Solution

Voltammetry of Platinum in Artificial Perilymph Solution

The Glutamate Receptor Subunit δ1 Is Highly Expressed in Hair Cells of the Auditory and Vestibular Systems

SNARE complex at the ribbon synapses of cochlear hair cells: analysis of synaptic vesicle‐ and synaptic membrane‐associated proteins

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