Inhibition by tetanus and botulinum A toxin of the release of [3H]noradrenaline and [3H]GABA from rat brain homogenate

Rat brain homogenate was preloaded with [3H]noradrenaline or [3H]GABA and stimulated with high K+. Tetanus toxin and botulinum A neurotoxin partially prevent the evoked [3H]noradrenaline release in the same range of toxin concentrations starting below 10−10M. In contrast, release of γ-amino butyric acid (GABA) is much more sensitive to tetanus than to botulinum A toxin.