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Szepesy J, Humli V, Farkas J, Miklya I, Tímár J, Tábi T, Gáborján A, Polony G, Szirmai Á, Tamás L, Köles L, Vizi ES, Zelles T. Chronic Oral Selegiline Treatment Mitigates Age-Related Hearing Loss in BALB/c Mice. Int J Mol Sci 2021; 22:2853. [PMID: 33799684 PMCID: PMC7999597 DOI: 10.3390/ijms22062853] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 12/20/2022] Open
Abstract
Age-related hearing loss (ARHL), a sensorineural hearing loss of multifactorial origin, increases its prevalence in aging societies. Besides hearing aids and cochlear implants, there is no FDA approved efficient pharmacotherapy to either cure or prevent ARHL. We hypothesized that selegiline, an antiparkinsonian drug, could be a promising candidate for the treatment due to its complex neuroprotective, antioxidant, antiapoptotic, and dopaminergic neurotransmission enhancing effects. We monitored by repeated Auditory Brainstem Response (ABR) measurements the effect of chronic per os selegiline administration on the hearing function in BALB/c and DBA/2J mice, which strains exhibit moderate and rapid progressive high frequency hearing loss, respectively. The treatments were started at 1 month of age and lasted until almost a year and 5 months of age, respectively. In BALB/c mice, 4 mg/kg selegiline significantly mitigated the progression of ARHL at higher frequencies. Used in a wide dose range (0.15-45 mg/kg), selegiline had no effect in DBA/2J mice. Our results suggest that selegiline can partially preserve the hearing in certain forms of ARHL by alleviating its development. It might also be otoprotective in other mammals or humans.
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MESH Headings
- Administration, Oral
- Aging/physiology
- Animals
- Antiparkinson Agents/administration & dosage
- Antiparkinson Agents/pharmacology
- Auditory Threshold/drug effects
- Auditory Threshold/physiology
- Disease Models, Animal
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Evoked Potentials, Auditory, Brain Stem/physiology
- Hearing Loss, Sensorineural/drug therapy
- Hearing Loss, Sensorineural/physiopathology
- Humans
- Male
- Mice, Inbred BALB C
- Mice, Inbred DBA
- Protective Agents/administration & dosage
- Protective Agents/pharmacology
- Selegiline/administration & dosage
- Selegiline/pharmacology
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- Mice
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Affiliation(s)
- Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, H-1083 Budapest, Hungary; (A.G.); (G.P.); (Á.S.); (L.T.)
| | - Viktória Humli
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
| | - János Farkas
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
| | - Ildikó Miklya
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
| | - Júlia Tímár
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
| | - Tamás Tábi
- Department of Pharmacodynamics, Semmelweis University, H-1089 Budapest, Hungary;
| | - Anita Gáborján
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, H-1083 Budapest, Hungary; (A.G.); (G.P.); (Á.S.); (L.T.)
| | - Gábor Polony
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, H-1083 Budapest, Hungary; (A.G.); (G.P.); (Á.S.); (L.T.)
| | - Ágnes Szirmai
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, H-1083 Budapest, Hungary; (A.G.); (G.P.); (Á.S.); (L.T.)
| | - László Tamás
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, H-1083 Budapest, Hungary; (A.G.); (G.P.); (Á.S.); (L.T.)
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
- Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary
| | - Elek Sylvester Vizi
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, H-1083 Budapest, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary; (J.S.); (V.H.); (J.F.); (I.M.); (J.T.); (L.K.); (E.S.V.)
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, H-1083 Budapest, Hungary
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Polony G, Humli V, Andó R, Aller M, Horváth T, Harnos A, Tamás L, Vizi ES, Zelles T. Protective effect of rasagiline in aminoglycoside ototoxicity. Neuroscience 2014; 265:263-73. [PMID: 24508748 DOI: 10.1016/j.neuroscience.2014.01.057] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/13/2014] [Accepted: 01/29/2014] [Indexed: 12/28/2022]
Abstract
Sensorineural hearing losses (SNHLs; e.g., ototoxicant- and noise-induced hearing loss or presbycusis) are among the most frequent sensory deficits, but they lack effective drug therapies. The majority of recent therapeutic approaches focused on the trials of antioxidants and reactive oxygen species (ROS) scavengers in SNHLs. The rationale for these studies was the prominent role of disturbed redox homeostasis and the consequent ROS elevation. Although the antioxidant therapies in several animal studies seemed to be promising, clinical trials have failed to fulfill expectations. We investigated the potential of rasagiline, an FDA-approved monomanine oxidase type B inhibitor (MAO-B) inhibitor type anti-parkinsonian drug, as an otoprotectant. We showed a dose-dependent alleviation of the kanamycin-induced threshold shifts measured by auditory brainstem response (ABR) in an ototoxicant aminoglycoside antibiotic-based hearing loss model in mice. This effect proved to be statistically significant at a 6-mg/kg (s.c.) dose. The most prominent effect appeared at 16kHz, which is the hearing sensitivity optimum for mice. The neuroprotective, antiapoptotic and antioxidant effects of rasagiline in animal models, all targeting a specific mechanism of aminoglycoside injury, may explain this otoprotection. The dopaminergic neurotransmission enhancer effect of rasagiline might also contribute to the protection. Dopamine (DA), released from lateral olivocochlear (LOC) fibers, was shown to exert a protective action against excitotoxicity, a pathological factor in the aminoglycoside-induced SNHL. We have shown that rasagiline enhanced the electric stimulation-evoked release of DA from an acute mouse cochlea preparation in a dose-dependent manner. Using inhibitors of voltage-gated Na(+)-, Ca(2+) channels and DA transporters, we revealed that rasagiline potentiated the action potential-evoked release of DA by inhibiting the reuptake. The complex, multifactorial pathomechanism of SNHLs most likely requires drugs acting on multiple targets for effective therapy. Rasagiline, with its multi-target action and favorable adverse effects profile, might be a good candidate for a clinical trial testing the otoprotective indication.
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Affiliation(s)
- G Polony
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary; Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - V Humli
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - R Andó
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary
| | - M Aller
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - T Horváth
- Department of Otorhinolaryngology, Bajcsy-Zsilinszky Hospital, Budapest, Hungary; Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - A Harnos
- Department of Biomathematics and Informatics, Szent István University, Budapest, Hungary
| | - L Tamás
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary
| | - E S Vizi
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary; Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - T Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary; Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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Lendvai B, Halmos GB, Polony G, Kapocsi J, Horváth T, Aller M, Sylvester Vizi E, Zelles T. Chemical neuroprotection in the cochlea: The modulation of dopamine release from lateral olivocochlear efferents. Neurochem Int 2011; 59:150-8. [DOI: 10.1016/j.neuint.2011.05.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 05/12/2011] [Accepted: 05/17/2011] [Indexed: 01/16/2023]
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Doleviczényi Z, Halmos G, Répássy G, Vizi ES, Zelles T, Lendvai B. Cochlear dopamine release is modulated by group II metabotropic glutamate receptors via GABAergic neurotransmission. Neurosci Lett 2005; 385:93-8. [PMID: 15927369 DOI: 10.1016/j.neulet.2005.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Revised: 04/22/2005] [Accepted: 05/09/2005] [Indexed: 10/25/2022]
Abstract
Dopamine (DA), released from the lateral olivocochlear efferent fibers, is suggested to be neuroprotective against ischemia and noise exposure in the mammalian cochlea because it can reduce the postsynaptic excitotoxic effect of glutamate on the dendrite of the afferent auditory neuron. Using in vitro microvolume superfusion method on isolated guinea pig cochlea preparation, we found that the selective mGluR2/3 agonist (2R,4R)-aminopyrrolidine-2,4-dicarboxylic acid (2R,4R-APDC) significantly increased the release of DA in a dose-dependent manner. Other mGluR agonists, acting on groups I and III receptors (3,5-dihydroxyphenylglycine, amino-4-phosphonobutyric acid) and antagonists (2-methyl-6-(phenylethynyl)pyridine), (2S)-2-amino-2-(1S,2S-2-carboxycyclopronan-1-yl-3-(xanth9-yl)propanoic acid, alpha-methylserine-O-phosphate), were ineffective. The GABA(A) antagonist bicuculline (10microM) could antagonize the effect of 2R,4R-APDC suggesting that the mGluR-mediated enhancement of DA release was most likely attributable to a disinhibitory mechanism involving local GABAergic fibers. Bicuculline alone could also elevate the DA outflow indicating that cochlear GABA controls local DA release tonically. Our findings expand the view on the local effects of glutamate in the cochlea by showing the ability of the excitatory neurotransmitter to alleviate its own action on type I afferents via mGluRs and initiate a neuroprotective mechanism.
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MESH Headings
- Animals
- Cochlea/drug effects
- Cochlea/metabolism
- Cytoprotection/drug effects
- Cytoprotection/physiology
- Dopamine/metabolism
- Dose-Response Relationship, Drug
- Drug Interactions
- Efferent Pathways/metabolism
- Excitatory Amino Acid Agonists/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- GABA Antagonists/pharmacology
- GABA-A Receptor Antagonists
- Guinea Pigs
- Hair Cells, Auditory, Inner/drug effects
- Hair Cells, Auditory, Inner/metabolism
- Male
- Neural Inhibition/drug effects
- Neural Inhibition/physiology
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Presynaptic Terminals/metabolism
- Receptors, GABA-A/metabolism
- Receptors, Metabotropic Glutamate/drug effects
- Receptors, Metabotropic Glutamate/metabolism
- Spiral Ganglion/drug effects
- Spiral Ganglion/metabolism
- Synapses/drug effects
- Synapses/metabolism
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- Zoltán Doleviczényi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43., H-1083 Budapest, Hungary
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Halmos G, Doleviczényi Z, Répássy G, Kittel A, Vizi ES, Lendvai B, Zelles T. D2 autoreceptor inhibition reveals oxygen-glucose deprivation-induced release of dopamine in guinea-pig cochlea. Neuroscience 2005; 132:801-9. [PMID: 15837140 DOI: 10.1016/j.neuroscience.2005.01.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2005] [Indexed: 11/29/2022]
Abstract
Dopamine (DA), released from the lateral olivocochlear (LOC) efferent terminals, the efferent arm of the short-loop feedback in the cochlea, is considered as a protective factor in the inner ear since it inhibits auditory nerve dendrite firing in ischemia- or noise-induced excitotoxicity leading to sensorineural hearing loss (SNHL). In the present study we investigated the effect of oxygen-glucose deprivation (OGD), an in vitro ischemia model, on guinea-pig cochlear [(3)H]DA release in a microvolume superfusion system. We found that OGD alone failed to induce a detectable elevation of [(3)H]DA level, but in the presence of specific D(2) receptor antagonists, sulpiride and L-741,626, it evoked a significant increase in the extracellular concentration of [(3)H]DA. D(2) negative feedback receptors are involved not exclusively in the regulation of synthesis and vesicular release of DA, but also in the activation of its reuptake. Thus, D(2) receptor antagonism interferes with the powerful reuptake of DA from the extracellular space. To explore the underlying mechanism of this DA-releasing effect we applied nomifensine and found that the effect of OGD on cochlear DA release in the presence of D(2) antagonists could be inhibited by this selective DA uptake inhibitor. This finding indicates that the OGD-evoked DA release was mainly mediated through the reverse operation of the DA transporter. The two structurally different D(2) antagonists also augmented the electrical field stimulation-evoked release of DA proving the presence of D(2) autoreceptors on dopaminergic LOC terminals. Our results confirm the presence and role of D(2) DA autoreceptors in the regulation of DA release from LOC efferents, and suggest a protective local mechanism during ischemia which involves the direct transporter-mediated release of DA. Increasing the release of the protective transmitter DA locally in the inner ear may form the basis of future new therapeutic strategies in patients suffering from SNHL.
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Affiliation(s)
- G Halmos
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083 Budapest, Hungary
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Le Prell CG, Halsey K, Hughes LF, Dolan DF, Bledsoe SC. Disruption of lateral olivocochlear neurons via a dopaminergic neurotoxin depresses sound-evoked auditory nerve activity. J Assoc Res Otolaryngol 2005; 6:48-62. [PMID: 15735934 PMCID: PMC2504639 DOI: 10.1007/s10162-004-5009-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Accepted: 10/29/2004] [Indexed: 11/30/2022] Open
Abstract
We applied the dopaminergic (DA) neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to the guinea pig cochlear perilymph. Immunolabeling of lateral olivocochlear (LOC) neurons using antibodies against synaptophysin was reduced after the MPTP treatment. In contrast, labeling of the medial olivocochlear innervation remained intact. As after brainstem lesions of the lateral superior olive (LSO), the site of origin of the LOC neurons, the main effect of disrupting LOC innervation of the cochlea via MPTP was a depression of the amplitude of the compound action potential (CAP). CAP amplitude depression was similar to that produced by LSO lesions. Latency of the N1 component of the CAP, and distortion product otoacoustic emission amplitude and adaptation were unchanged by the MPTP treatment. This technique for selectively lesioning descending LOC efferents provides a new opportunity for examining LOC modulation of afferent activity and behavioral measures of perception.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacology
- Action Potentials
- Adaptation, Physiological/drug effects
- Adaptation, Physiological/physiology
- Animals
- Cochlear Nerve/physiology
- Cochlear Nucleus/pathology
- Cochlear Nucleus/physiology
- Denervation
- Dopamine/physiology
- Dopamine Agents/pharmacology
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Evoked Potentials, Auditory, Brain Stem/physiology
- Female
- Guinea Pigs
- Immunohistochemistry
- Male
- Neurotoxins/pharmacology
- Olivary Nucleus/pathology
- Olivary Nucleus/physiology
- Otoacoustic Emissions, Spontaneous/drug effects
- Otoacoustic Emissions, Spontaneous/physiology
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Affiliation(s)
- Colleen G Le Prell
- Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor, MI 48109-0506, USA.
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Abstract
Voltage-dependent sodium channels (VDSC) are an important class of ion channels in excitable cells, where they are responsible for the generation and conduction of action potential. In addition, the release of neurotransmitters from nerve terminals is influenced by sodium channel activity. The function of VDSC is subject to modulation by various neurotoxins, such as scorpion toxins, which have long been used as tools in the investigation of neurotransmitter release. This opens an interesting perspective concerning modulation of neurotransmission via pharmacological manipulation of sodium channel properties, which can lead to a better understanding of their physiological and pathological roles. Here we briefly review the studies of neurotoxins acting on sodium channels, focusing primarily on the view of the mechanisms of neurotransmitter release.
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Affiliation(s)
- André Ricardo Massensini
- Núcleo de Neurociências, Departamento de Fisiologia e Biofisica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Carlos 6627, Belo Horizonte-MG, Brazil
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Bicalho AFX, Guatimosim C, Prado MAM, Gomez MV, Romano-Silva MA. Investigation of the modulation of glutamate release by sodium channels using neurotoxins. Neuroscience 2002; 113:115-23. [PMID: 12123690 DOI: 10.1016/s0306-4522(02)00139-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The modulation of neurotransmitter release by calcium channels is well established, yet, sodium channels were regarded mainly as charge carriers. Many lines of evidence suggest a more fine-tuning role played by sodium channels. Using rat cerebrocortical isolated nerve endings (synaptosomes) and two toxins that have separate sites of action on sodium channels and provoke distinct changes in channel kinetics, we were able to show that depending on the rate of increase in channel conductance, the outcome in terms of neurotransmitter release and calcium channel types coupled to that event are different. Mainly, our study focused on veratridine, an alkaloid from lilaceous plants that binds to sodium channel toxin site 2, and tityustoxin, a toxin purified from the venom of the Brazilian yellow scorpion Tityus serrulatus that binds to site 3. Veratridine induces a slower increase in intrasynaptosomal sodium and calcium concentrations, slower depolarization, delayed exocytosis and a slower and predominantly calcium-independent glutamate release, when compared to tityustoxin.Thus, we have used these two toxins to investigate the events that start with sodium entry and culminate with the release of glutamate in isolated nerve endings (synaptosomes) from rat cerebral cortex. With that in mind we measured intrasynaptosomal free sodium concentration [Na(+)](i), intrasynaptosomal free calcium concentration [Ca(2+)](i), membrane potential, exocytosis and glutamate release using fluorescent probes.
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Affiliation(s)
- A F X Bicalho
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Belo Horizonte 31270-901, MG, Brazil
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Halmos G, Lendvai B, Gáborján A, Baranyi M, Szabó LZ, Csokonai Vitéz L. Simultaneous measurement of glutamate and dopamine release from isolated guinea pig cochlea. Neurochem Int 2002; 40:243-8. [PMID: 11741007 DOI: 10.1016/s0197-0186(01)00065-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Glutamate is proved to be a neurotransmitter in the mammalian cochlea, transmitting signals between the inner hair cells and the afferent cochlear nerve terminals. The transmission in this synapse is modulated by the lateral olivocochlear efferent fibers by releasing dopamine and other neurotransmitters. This study undertakes to measure simultaneously the release of dopamine and glutamate from isolated guinea pig cochleae. We combined the in vitro microvolume superfusion method, that uses liquid scintillation analysis, to measure [3H]dopamine with high pressure liquid chromatography (HPLC) to determine the glutamate content of the superfusate at rest and during stimulation. The release of both neurotransmitters was significantly increased when electrical field stimulation was applied at a 10 Hz rate. The nonselective sodium-channel inhibitor tetrodotoxin (TTX) at 1 microM completely blocked the effect of stimulation, indicating the neural origin of both dopamine and glutamate. The dopamine receptor antagonist sulpiride at 100 microM and the dopamine receptor agonist bromocriptine at 20 microM did not change the release of glutamate. In contrast, both bromocriptine and sulpiride significantly increased the stimulation-evoked release of dopamine. The effect of sulpiride is most likely due to the blockade of dopamine autoreceptor. Possible explanations why bromocriptine increased the release include: (1) its partional agonist activity; (2) desensitizations of dopamine autoreceptors; or (3) the higher D1 receptor activity of bromocriptine than sulpiride. This study could provide further insights about the role of dopamine and glutamate in cochlear neurotransmission.
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Affiliation(s)
- György Halmos
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Gáborján A, Halmos G, Répássy G, Vizi ES. A new aspect of aminoglycoside ototoxicity: impairment of cochlear dopamine release. Neuroreport 2001; 12:3327-30. [PMID: 11711880 DOI: 10.1097/00001756-200110290-00036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aminoglycoside ototoxicity is a well-documented process via several pathophysiological pathways. The protective role of cochlear dopamine, released from the lateral olivocochlear efferents, was implicated previously in case of ischemia or acoustic trauma, as it postsynaptically inhibits the effect of excessively released glutamate from the hair cells. In our in vitro superfusion experiments we showed that neomycin dose- dependently inhibits the dopamine release from isolated guinea pig cochlea, while gentamicin and kanamycin was ineffective on it. After chronic application of neomycin the dopamine outflow did not change significantly, suggesting an adaptive process. In our experiments we have found a possibly new action site of one of the aminoglycoside antibiotics, neomycin.
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Affiliation(s)
- A Gáborján
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, P.O. Box 67, H-1450 Budapest, Hungary
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