Potassium induced release of GABA and other substances from the guinea pig cochlea

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

doi:10.1016/0378-5955(90)90141-b

Cited by 42 publications

(14 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Regarding the possibility of GABA as an efferent transmitter, ex vivo experiments have shown a potassium induced release of GABA in the guinea pig cochlea (Bobbin et al,1990a,b), while local application of GABA hyperpolarized apical OHCs from the same species (Gitter and Zenner, 1992; Plinkert et al, 1993) and reduced OHC electromotility and stiffness (Sziklai et al,1996; Batta et al, 2004). However, locally-applied GABA had no effect on OHCs in other studies (Bobbin et al, 1990a,b; Evans et al, 1996).…”

Section: Cellular Mechanism Of Moc Efferent Inhibitionmentioning

confidence: 99%

Modulation of hair cell efferents

Wersinger

Fuchs

2011

Hearing Research

View full text Add to dashboard Cite

Outer hair cells (OHCs) amplify the sound-evoked motion of the basilar membrane to enhance acoustic sensitivity and frequency selectivity. Medial olivocochlear (MOC) efferents inhibit OHCs to reduce the sound-evoked response of cochlear afferent neurons. OHC inhibition occurs through the activation of postsynaptic α9α10 nicotinic receptors tightly coupled to calcium-dependent SK2 channels that hyperpolarize the hair cell. MOC neurons are cholinergic but a number of other neurotransmitters and neuromodulators have been proposed to participate in efferent transmission, with emerging evidence for both pre-and postsynaptic effects. Cochlear inhibition in vivo is maximized by repetitive activation of the efferents, reflecting facilitation and summation of transmitter release onto outer hair cells. This review summarizes recent studies on cellular and molecular mechanisms of cholinergic inhibition and the regulation of those molecular components, in particular the involvement of intracellular calcium. Facilitation at the efferent synapse is compared in a variety of animals, as well as other possible mechanisms of modulation of ACh release. These results suggest that short-term plasticity contributes to effective cholinergic inhibition of hair cells.

show abstract

Section: Cellular Mechanism Of Moc Efferent Inhibitionmentioning

confidence: 99%

Modulation of hair cell efferents

Wersinger

Fuchs

2011

Hearing Research

View full text Add to dashboard Cite

show abstract

“…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: 99%

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

Safieddine

Wenthold

1997

J. Neurosci.

View full text Add to dashboard Cite

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

show abstract

“…We used transmission electron microscope (AFM) and HPLC 8 to evaluate the characteristics of RES-BSANP. Kunming mice (female, weight 18-20 g; from the Institute of Oncology of Harbin Medical University) were randomly divided into 2 groups with 5 mice in each group as follows: group 1 was designated the control group and treated with RES, and group 2 was designated the experimental group and treated with RES-BSANP.…”

Section: Evaluation Of the Characteristics Of Res-bsanp And Hplc Analmentioning

confidence: 99%

Anticancer Activity and Molecular Mechanism of Resveratrol–Bovine Serum Albumin Nanoparticles on Subcutaneously Implanted Human Primary Ovarian Carcinoma Cells in Nude Mice

Guo

Peng

Yao

et al. 2010

Cancer Biotherapy and Radiopharmaceuticals

View full text Add to dashboard Cite

This study investigates the antitumor effects and functional mechanism of resveratrol-bovine serum albumin nanoparticles (RES-BSANP) on human primary ovarian carcinoma cells in nude mice. An implanted tumor model was established by injecting a suspension of the human primary ovarian cancer cell SKOV 3 into the subcutaneous tissue of nude mice. The tumor-bearing mice (n ¼ 32) were randomly divided into 8 groups, which received intraperitoneal injections of normal saline (0.9%, 0.5 mL), BSA (1.5 mg/kg, 0.5 mL), or RES-BSANP or RES (200, 100, and 50 mg/kg, 0.5 mL), respectively, once a week for 4 weeks. The in vivo antitumor efficacy was evaluated by measurement of tumor volume, whereas morphological alterations were observed by transmission electron microscope (atomic force microscopy); TUNEL assays and immunoblotting for apoptotic and cell proliferation proteins were carried out to elucidate the possible mechanism. RES-BSANP was found to exhibit certain highly desirable characteristics such as innocuity, better dispersity, and water solubility; it affected the in vivo tissue/organ distribution of RES in a remarkable manner. The administration of RES-BSANP significantly retarded the growth of carcinomas in nude mice from the third week onwards, and the inhibition rate was markedly higher than in mice treated with RES (52.43% vs. 46.34%, p < 0.05), without causing weight loss ( p > 0.05). Simultaneously, apoptotic and necrotic morphological characteristics were observed with electron microscopy in the tumor tissues of treated mice. TUNEL staining revealed that the tumors from RES-BSANPtreated mice exhibited a similar apoptotic index as RES control tumors. Western blot analysis of the protein expression profiles revealed that part of the mechanism may be mediated by triggering the release of cytochrome c from the intermembrane space and upregulating the expression of caspase-9 and caspase-3, suggesting that the mitochondrial apoptotic pathway was being activated.

show abstract

Potassium induced release of GABA and other substances from the guinea pig cochlea

Cited by 42 publications

References 22 publications

Modulation of hair cell efferents

Modulation of hair cell efferents

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

Anticancer Activity and Molecular Mechanism of Resveratrol–Bovine Serum Albumin Nanoparticles on Subcutaneously Implanted Human Primary Ovarian Carcinoma Cells in Nude Mice

Contact Info

Product

Resources

About