Intracellular free Ca 2+ concentration ([Ca 2+ ];) in spiral ganglion cells (SGC) of guinea pig was measured using the fura-2 fluorescence method. Application of high-K + external solution increased [Ca 2+ ] i . [Ca 2+ ] i elevation was suppressed by either depletion of external Ca 2+ or application of the dihydropyridine Ca 2+ channel antagonist, nicardipine. One of the putative hair cell afferent nerve neurotransmitters, L-glutamate (Glu), induced [Ca 2+ ] 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 Ca 2+ or application of nicardipine, indicating that Glu-induced [Ca 2+ ] i elevation is mainly carried out by the voltage- dependent Ca 2+ channel in SGC.
All Science Journal Classification (ASJC) codes