Thermal influence on intracellular calcium concentration in vestibular hair cells isolated from the guinea pig. A preliminary report.

Caloric responses to intracellular calcium homeostasis of vestibular hair cells isolated from the guinea pig were examined. An increase in intracellular free calcium ion concentration ([Ca2+]i) in the isolated cells was observed by direct heat stimulation. The cells, dissociated enzymatically or mechanically, were stimulated by perfusion of solution, in the temperature range of 2.2-5.2 degrees C. The [Ca2+]i was analysed using a digital imaging microscope and the Ca2+ sensitive dye, Fura-2. There was an increase in [Ca2+]i in both Types I and II vestibular hair cells with this heat stimulation. The direct thermal influence on vestibular sensory cells is discussed in relation to mechanisms involved in caloric nystagmus.