Aconitine

Neurotoxin. Activates tetrodotoxin-sensitive Na+ channels, inducing presynaptic depolarization, thus blocking the nerve action potential which, in turn, blocks the release of neurotransmitters and decreases the end plate potential at the neuromuscular junction. Aconitine also blocks norepinephrine reuptake. In the heart, aconitine induces ventricular tachycardia after intracoronary injection. In cultured ventricular myocytes, aconitine increases the duration of the action potential and induces the appearance of early after depolarization. Used in producing heart arrhythmia in experimental animals.