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Outward K currents and electrical resonance of frog (Rana esculenta) saccular hair cells isolated enzymatically with bacterial protease VIII were investigated using the perforated patch-clamp method. Under voltage-clamp conditions we identified two K currents, a voltage-dependent K (K(V)) current, and a partially inactivating iberiotoxin-sensitive K (BK)(More)
1. The mechanism of verapamil block of the delayed rectifier K currents (I K(DR)) in chick dorsal root ganglion (DRG) neurons was investigated using the whole-cell patch clamp configuration. In particular we focused on the location of the blocking site, and the active form (neutral or charged) of verapamil using the permanently charged verapamil analogue(More)
In adult mouse trigeminal ganglion (TG) neurones we identified three neuronal subpopulations, defined in terms of their firing response to protracted depolarizations, namely MF neurones, characterized by a multiple tonic firing; DMF neurones, characterized by a delay before the beginning of repetitive firing; and SS neurones, characterized by a strongly(More)
The effects of verapamil and related phenylalkylamines on neuronal excitability were investigated in isolated neurons of rat intracardiac ganglia using whole-cell perforated patch-clamp recording. Verapamil (>/=10 microM) inhibits tonic firing observed in response to depolarizing current pulses at 22 degrees C. The inhibition of discharge activity is not(More)
The properties of single Ca2+-activated K+ (BK) channels in neonatal rat intracardiac neurons were investigated using the patch-clamp recording technique. In symmetrical 140 mM K+, the single-channel slope conductance was linear in the voltage range -60/+60 mV, and was 207+/-19 pS. Na+ ions were not measurably permeant through the open channel. Channel(More)
Short QT3 syndrome (SQT3S) is a cardiac disorder characterized by a high risk of mortality and associated with mutations in Kir2.1 (KCNJ2) channels. The molecular mechanisms leading to channel dysfunction, cardiac rhythm disturbances and neurodevelopmental disorders, potentially associated with SQT3S, remain incompletely understood. Here, we report on(More)
We report here the expression in C2C12 myoblasts of the intermediate-conductance Ca2+-activated K+ (IK(Ca)) channel. The IK(Ca) current, recorded under perforated-patch configuration, had a transient time course when activated by ionomycin (0.5 microM; peak current density 26.2 +/- 3.7 pA/pF; n = 10), but ionomycin (0.5 microM) +(More)
A biophysical analysis of the voltage-gated K (Kv) currents of frog saccular hair cells enzymatically isolated with bacterial protease VIII was carried out, and their contribution to the cell electrical response was addressed by a modeling approach. Based on steady-state and kinetic properties of inactivation, two distinct Kv currents were found: a fast(More)
Spontaneous membrane voltage oscillations were found in 27 of 130 isolated frog saccular hair cells. Voltage oscillations had a mean peak-to-peak amplitude of 23 mV and a mean oscillatory frequency of 4.6 Hz. When compared with non-oscillatory cells, oscillatory cells had significantly greater hyperpolarization-activated and lower depolarization-activated(More)
Familial hemiplegic migraine type-1 (FHM1), a monogenic subtype of migraine with aura, is caused by gain-of-function mutations in Ca(V)2.1 (P/Q-type) calcium channels. The consequences of FHM1 mutations on the trigeminovascular pathway that generates migraine headache remain largely unexplored. Here we studied the calcium currents and excitability(More)