title: Measurement of intracellular free Ca2+ concentration in guinea pig spiral ganglion cells.
abstract: Intracellular free Ca2+ concentration ([Ca2+]i) in spiral ganglion cells (SGC) of guinea pig was measured using the fura-2 fluorescence method. Application of high-K+ external solution increased [Ca2+]i. [Ca2+]i elevation was suppressed by either depletion of external Ca2+ or application of the dihydropyridine Ca2+ channel antagonist, nicardipine. One of the putative hair cell afferent nerve neurotransmitters, L-glutamate (Glu), induced [Ca2+]i elevation in SGC. Pharmacological studies suggested that the Glu receptor may be a non-NMDA subtype. Glu-induced response was suppressed by either depletion of external Ca2+ or application of nicardipine, indicating that Glu-induced [Ca2+]i elevation is mainly carried out by the voltage-dependent Ca2+ channel in SGC.
authors.affiliation: Department of Otorhinolaryngology, Miyazaki Medical College, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Shimozono
authors.forename: T
authors.initials: T
authors.lastname: Tono
authors.forename: T
authors.initials: T
authors.lastname: Morimitsu
authors.forename: T
authors.initials: T
authors.lastname: Nakagawa
authors.forename: S
authors.initials: S
authors.lastname: Komune
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis* / Q000502:physiology; D015220:Calcium Channels / Q000187:drug effects; D003051:Cochlea / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D016257:Fura-2; D018698:Glutamic Acid / Q000494:pharmacology; D006168:Guinea Pigs; D009529:Nicardipine / Q000494:pharmacology; D013136:Spiral Ganglion / Q000737:chemistry* / Q000502:physiology; D013997:Time Factors
chemical_list: D015220:Calcium Channels; D018698:Glutamic Acid; D009529:Nicardipine; D002118:Calcium; D016257:Fura-2