MOLECULAR PHARMACOLOGY, 48:451-458 (1995). Novel Pharmacological Properties of Transient Potassium Currents in Central Neurons Revealed by N-Bromoacetamide and Other Chemical Modifiers

The chemical modifiers N-bromoacetamide (NBA), N-bromo-succinimide (NBS), and chloramine-T (ChT) are commonly used to remove fast inactivation of sodium currents and transient potassium currents (l,J. In the present study, I examined the effects of these chemical modifiers as well as of others on ‘A in neurons dissociated from several brain regions. External appli-cation of NBA irreversibly inhibited ‘A ’ with higher NBA concen-trations increasing the rate of inhibition. The current kinetics, however, were not altered by external NBA at any concentra-tion. ‘A was also inhibited by internal NBA but only at high concentrations, and the rate of inhibition was much slower. The current kinetics were not altered by internal NBA at any con-centration. NBA is a nonspecific chemical reagent that can modify a protein at several target amino acids. The NBA-induced irreversible inhibition of ‘A was reproduced by externa