title: pH modulates the vestibular afferent discharge and its response to excitatory amino acids.
abstract: In the isolated inner ear of the axolotl (Ambystoma tigrinum) acid pH decreased and basic pH increased the resting and mechanically evoked spike discharge of semicircular canal afferent neurons. Variations in pH also modified the afferent neuron response to N-methyl-D-aspartic acid (NMDA) acid and to (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). Responses to both excitatory amino acid agonists increased at pH 7.8 (41% and 22%, respectively) and decreased by perfusion of the preparation with a saline solution, of pH 7.0 (28% in both cases). These results indicate that vestibular endorgans have a significant sensitivity to pH that could play a significant role in various pathological states, and may also contribute to the post-transductional processing of sensory information.
authors.affiliation: Instituto de Fisiología, BUAP, Universidad Autónoma de Puebla, Apartado Postal 406, Puebla, Pue. 72000, México. axolotl@siu.buap.mx
authors.forename: Rosario
authors.initials: R
authors.lastname: Vega
authors.forename: Francisco
authors.initials: F
authors.lastname: Mercado
authors.forename: Hortencia
authors.initials: H
authors.lastname: Chávez
authors.forename: Agenor
authors.initials: A
authors.lastname: Limón
authors.forename: Angélica
authors.initials: A
authors.lastname: Almanza
authors.forename: Aída
authors.initials: A
authors.lastname: Ortega
authors.forename: Maria Eugenia
authors.initials: ME
authors.lastname: Pérez
authors.forename: Enrique
authors.initials: E
authors.lastname: Soto
mesh_terms: D000557:Ambystoma; D000818:Animals; D015214:Antigens, Differentiation, Myelomonocytic / Q000494:pharmacology; D018846:Excitatory Amino Acids / Q000494:pharmacology*; D005110:Extracellular Space / Q000502:physiology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects*; D007814:Larva / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D012665:Semicircular Canals / Q000187:drug effects*; D013997:Time Factors; D014157:Transcription Factors / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D015214:Antigens, Differentiation, Myelomonocytic; D018846:Excitatory Amino Acids; C075373:MNDA protein, human; D014157:Transcription Factors; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid