title: Different action of memantine and caroverine on glutamatergic transmission in the mammalian cochlea.
abstract: Glutamate is the major transmitter candidate between inner hair cells and the afferent neurons of the mammalian cochlea. We investigated the action of memantine (1-amino-3,5-dimethyl-adamantane) and the quinoxaline derivative caroverine [1-diethylaminoethyl-3,8-(p-methoxybenzyl)-1,2-dihydro-quinoxaline-dione] on the glutamatergic transmission in the guinea pig cochlea utilizing extracellular recording techniques and microiontophoretic ejection of substances. While memantine was able to inhibit the NMDA (N-methyl-D-aspartate)-induced firing, the AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid)-stimulated activity was unaffected. In contrast, caroverine could block both NMDA- as well as AMPA-induced firing. As memantine and caroverine are currently in clinical use, these substances could be introduced to the treatment of several cochlear disorders.
authors.affiliation: ENT Department, Technical University of Munich, Germany. e.oestreicher@lrz.tum.de
authors.forename: Elmar
authors.initials: E
authors.lastname: Oestreicher
authors.forename: Klaus
authors.initials: K
authors.lastname: Ehrenberger
authors.forename: Dominik
authors.initials: D
authors.lastname: Felix
mesh_terms: D000818:Animals; D003051:Cochlea / Q000187:drug effects* / Q000378:metabolism*; D015259:Dopamine Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism; D008559:Memantine / Q000493:pharmacokinetics / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000378:metabolism; D009475:Neurons, Afferent / Q000378:metabolism; D011810:Quinoxalines / Q000493:pharmacokinetics / Q000494:pharmacology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000378:metabolism
chemical_list: D015259:Dopamine Agents; D011810:Quinoxalines; D018698:Glutamic Acid; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D008559:Memantine; C000957:caroverine