Functional aspects of dexamethasone upregulated nicotinic acetylcholine receptors in C2C12 myotubes.

Three days of treatment with the glucocorticoid dexamethasone (1 nM-1 microM) induced a concentration-dependent up-regulation of muscle nicotinic acetylcholine receptor (nAChR) in C2C12 mouse myotubes (EC50 = 10 +/- 7.3 nM), as assessed by [3H]alpha-BuTx binding. The maximum increase in binding amounted 148 +/- 17.

Effects of an aminosteroid, ORG 6001, on various membrane phenomena of non-myelinated nerve fibres of the rat.

The aminosteroid ORG 6001 (3 alpha-amino-5 alpha-androstan-2 beta-ol-17-one hydrochloride) was shown to be a compound with a rather strong local anaesthetic action. Compound action potentials evoked in non-myelinated nerve fibres of the desheathed rat vagus with the single sucrose gap method showed, in presence of this drug, a decrease in amplitude and increase in conduction time comparable with the effect of lidocaine. Since the total membrane resistance represented by the amplitude of the electrotonic potential was not affected by ORG 6001, it is likely that ORG 6001 reduces the transient increase in sodium conductance during the action potential, a mechanism also postulated for lidocaine.

The effects of isoxsuprine on non-myelinated nerve fibres.

A study has been made of the effect of isoxsuprine on non-myelinated nerve fibres of the desheathed rabbit vagus. Isoxsuprine did not affect the membrane potential, the membrane resistance, or the sodium pump activity. Isoxsuprine diminished the amplitude and rise time of the compound action potential.