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1. The whole-cell patch-clamp technique was used to investigate the characteristics of two types of sodium current (INa) recorded at room temperature from small diameter (13-25 microns) dorsal root ganglion (DRG) cells, isolated from adult rats and maintained overnight in culture. 2. Sodium currents were isolated pharmacologically. Internal Cs+ and external(More)
Measurements have been made of gramicidin single-channel lifetimes in monoacylglycerol bilayers chosen so that their thickness ranged from above to below the length of the gramicidin channel. Contact angles, electrical capacities and bulk-phase interfacial tensions have also been determined for these systems. The mean channel lifetime decreased with the(More)
1. Whole-cell and single-channel Na+ currents were recorded from small (ca. 20 micron diameter) cells isolated from adult rat dorsal root ganglia (DRG). Currents were classified by their sensitivity to 0.3 microM tetrodotoxin (TTX), electrophysiological properties and single-channel amplitude. Cells were classified according to the types of current recorded(More)
We determined the effects of carbamazepine and phenytoin, anticonvulsant drugs used to treat neuropathic pain, on the heterogeneous population of Na+ channels in patch-clamped small cells from adult rat dorsal root ganglia. Both fast tetrodotoxin-sensitive (TTX-S) and slow TTX-resistant (TTX-R) currents were inhibited by 10-100 microM drug. TTX-R currents(More)
The effects of n-decanol, n-hexadecanol, n-octyl(oxyethylene)3 alcohol and cholesterol on gramicidin single-channel lifetime in planar lipid bilayers have been determined. The bilayers used were formed from a solution of monoolein in squalene. Measurements have also been made of the above compounds' effects on membrane thickness (as measured by electrical(More)
Monophasic compound action potentials were recorded from Rana sciatic nerves. Three distinct peaks were observed and designated A alpha, A delta and C. All peaks were abolished by replacement of the external medium with Na(+)-free solution. However, the C peak alone was unaffected by external application of 1 microM tetrodotoxin (TTX), both A peaks were(More)
The effects of methyl butyl ketone, methyl heptyl ketone and methyl pentanoate on the sodium current of the squid giant axon have been examined. The peak inward current in intact axons was reduced reversibly by each substance. Sodium currents were recorded in intracellularly perfused axons before and during exposure to the test substances and the records(More)
Phenol has various medical applications but can cause convulsions and cardiac arrhythmia suggestive of K+ channel block. We examined phenol inhibition of the delayed-rectifier RCK1 (Kv1.1) K+ channel cloned from rat brain and expressed in Xenopus laevis oocytes. Phenol (2.5 mM) caused a 43 +/- 5 mV depolarizing shift in the RCK1 half-activation voltage (Vg)(More)
Besides the fast tetrodotoxin-sensitive Na+ current, small dorsal root ganglion neurones of rats also possess a slower tetrodotoxin-resistant Na+ current. The blocking effect of commonly used local anaesthetics upon the tetrodotoxin-resistant Na+ current was investigated in the present paper. Dorsal root ganglia were dissected from adult rats and cells were(More)
The actions of members of the homologous series of alkyl cations CH3 (CH2)n-1 N+ (CH3)3 (Cn TMA) on the sodium current in giant axons of Loligo forbesi have been investigated. The substances tested correspond to n = 6, 8, 10, 12, 14 and 16. These cations only produced significant sodium current suppression when applied inside the axon. Actions on(More)