3,4-Diaminopyridine

3,4-Diaminopyridine is an experimental drug used in the treatment of Lambert-Eaton Syndrome. In Lambert-Eaton Syndrome, acetylcholine release is inhibited as antibodies meant to target characteristic cancers target Ca2+ channels on the prejunctional membrane instead. 3,4-Diaminopyridine works by blocking potassium channel efflux in nerve terminals so that action potential duration is increased. Ca2+ channels can then be open for longer time and allow greater acetylcholine release to stimulate muscle at end plate.

It has also been proposed for use in multiple sclerosis.