The amplitude and inactivation properties of the delayed potassium currents are regulated by protein kinase activity in hair cells of the frog semicircular canals.

摘要: In hair cells dissected from the frog crista ampullaris, combination of a calcium-dependent (IKCa) and purely voltage-dependent component (IKV) gives rise to delayed potassium current complex (IKD). These currents have been recently reported display slow depolarization-induced inactivation biphasic removal by hyperpolarization. The amplitude kinetics both IKCa IKV are drastically modulated previously unrecognized mechanism protein phosphorylation (sensitive kinase inhibitors H89 KT5823), which does not interfere with transient (IA) or calcium (ICa). IKD was stable in patched pipettes containing 8 mM ATP under perforated-patch; these conditions, 10 min treatment µM 1–10 KT5823 reduced mean 67% at +40 mV. Similarly affected isolated (ICa blocked Cd2+). Thus, large conductance can be activated depolarization, but it is made available cell variable extent that depends on membrane potential activity. total gKD ranged 4.6–44.0 nS control cells, according level steady-state inactivation, 1.4–2.7 after inhibition. When sinusoidal changes −70/−10 mV range were applied, mimic receptor response bundle deflection, proved main dynamically only one regulated PK: decreased outward charge during each cycle 60%. Phosphorylation appears amount depolarization fraction thereof rescued inactivation. balance between depolarizing transduction repolarizing current, eventually transmitter release cytoneural junction, therefore phosphorylation-mediated process.