s-nitro-n-acetylpenicillamine and gluconic-acid

Mammalian vestibular organs have two types of hair cell, type I and type II, which differ morphologically and electrophysiologically. Type I hair cells alone express an outwardly rectifying current, I(K, L), which activates at relatively negative voltages. We used whole cell and patch configurations to study I(K,L) in hair cells isolated from the sensory epithelia of rat semicircular canals. I(K,L) was potassium selective, blocked by 4-aminopyridine, and permeable to internal cesium. It activated with sigmoidal kinetics and was half-maximally activated at -74.5 +/- 1.6 mV (n = 35; range -91 to -50 mV). It was a very large conductance (91 +/- 8 nS at -37 mV; 35 nS/pF for a cell of average size). Patch recordings from type I cells revealed a candidate ion channel with a conductance of 20-30 pS. Because I(K,L) was activated at the resting potential, the cells had low input resistances (R(m)): median 25 MOmega at -67 mV versus 1.3 GOmega for type II cells. Consequently, injected currents comparable to large transduction currents (300 pA) evoked small (

Topics: 4-Aminopyridine; 8-Bromo Cyclic Adenosine Monophosphate; Animals; Cyclic GMP; Gluconates; Guanylate Cyclase; Hair Cells, Vestibular; Membrane Potentials; Molsidomine; Nitric Oxide; Nitric Oxide Donors; Patch-Clamp Techniques; Penicillamine; Potassium; Potassium Channel Blockers; Rats; Rats, Long-Evans; Semicircular Canals; Signal Transduction