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Mechanical stimuli are thought to open the transduction channels of a hair cell by tensing elastic components, the gating springs, that pull directly on the channels. To test this model, we measured the stiffness of hair bundles during mechanical stimulation. A bundle's compliance increased by about 40% at the position where half of the channels opened.(More)
Calcium ions serve as intracellular messengers in 2 activities of hair cells: in conjunction with Ca2(+)-activated K+ channels, they produce the electrical resonance that tunes each cell to a specific frequency of stimulation, and they trigger the release of a chemical synaptic transmitter. Our experiments indicate that both of these functions are conducted(More)
Kinesin is a motor protein that uses energy derived from ATP hydrolysis to move organelles along microtubules. Using a new technique for measuring the movement produced in vitro by individual kinesin molecules, it is shown that a single kinesin molecule can move a microtubule for several micrometers. New information about the mechanism of force generation(More)
Ca(2+) influx through voltage-gated channels initiates the exocytotic fusion of synaptic vesicles to the plasma membrane. Here we show that RIM binding proteins (RBPs), which associate with Ca(2+) channels in hair cells, photoreceptors, and neurons, interact with alpha(1D) (L type) and alpha(1B) (N type) Ca(2+) channel subunits. RBPs contain three Src(More)
Mechanoelectrical transduction by hair cells of the frog's internal ear displays adaptation: the electrical response to a maintained deflection of the hair bundle declines over a period of tens of milliseconds. We investigated the role of mechanics in adaptation by measuring changes in hair-bundle stiffness following the application of force stimuli.(More)
The receptor current of hair cells from the bullfrog's sacculus was measured by voltage clamp recording across the isolated sensory epithelium. Several hundred hair cells were stimulated en masse by moving the overlying otolithic membrane with a piezoelectrically activated probe. As measured by optical recording of otolithic membrane motion, the step(More)
Hair cells of the inner ear are one of nature's great success stories, appearing early in vertebrate evolution and having a similar form in all vertebrate classes. They are specialized columnar epithelial cells, with an array of modified microvilli or stereocilia on their apical surface, interconnected by a series of linkages. The mechanical stimulus causes(More)
1. By the use of whole-cell and excised-patch tight-seal recording techniques, we studied ionic conductances in voltage-clamped solitary hair cells isolated from the bull-frog's sacculus. As a basis for assessing their contributions to hair cell electrical resonance, we developed kinetic models describing voltage-dependent Ca2+ and Ca2+-dependent K+(More)
The sense of hearing depends on fast, finely graded neurotransmission at the ribbon synapses connecting hair cells to afferent nerve fibers. The processing that occurs at this first chemical synapse in the auditory pathway determines the quality and extent of the information conveyed to the central nervous system. Knowledge of the synapse's input-output(More)
As in other excitable cells, the ion channels of sensory receptors produce electrical signals that constitute the cellular response to stimulation. In photoreceptors, olfactory neurons, and some gustatory receptors, these channels essentially report the results of antecedent events in a cascade of chemical reactions. The mechanoelectrical transduction(More)