The Journal of Neurophysiology Vol. 80 No. 4 October 1998, pp. 1647-1652
Copyright ©1998 The American Physiological Society

Modulation of Voltage-Activated Calcium Currents by Mechanical Stimulation in Rat Sensory Neurons

Yona Bouskila and Hugh Bostock

Sobell Department of Neurophysiology, Institute of Neurology, London WC2N 3BG, United Kingdom

Bouskila, Yona and Hugh Bostock. Modulation of voltage-activated calcium currents by mechanical stimulation in rat sensory neurons. J. Neurophysiol. 80: 1647-1652, 1998. We examined the effects of mechanical stress, induced by a stream of bath solution, on evoked action potentials, electrical excitability, and Ca²⁺ currents in rat dorsal root ganglion neurons in culture with the use of the whole cell patch-clamp technique. Action-potential duration was altered reversibly by flow in 39% of the 51 neurons tested, but membrane potential and excitability were unaffected. The flow-induced increases and decreases in action-potential duration were consistent with the different effects of flow on two types of Ca²⁺ channel, determined by voltage-clamp recordings of Ba²⁺ currents. Current through -conotoxin-sensitive (N-type) Ca²⁺ channels increased by an estimated 74% with flow, corresponding to 23% increase in the total high voltage-activated current, whereas current through low-threshold voltage-activated (T-type) channels decreased by 14%. We conclude that modulation of voltage-activated Ca²⁺ currents constitutes a route by which mechanical events can regulate Ca²⁺ influx in sensory neurons.

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