Amiloride has been shown to inhibit the epidermal growth factor (EGF)-induced pH changes in chicken granulosa and other cells and thus suggesting that EGF may increase intracellular pH by activating the Na+/H+ anti-porter system. Amiloride (0.1 mM) prevented endothelin-induced increase in intracellular pH. Amiloride was found to interact with adenosine A1 receptors in calf brain at a site distinct from the ligand binding site. It is a specific reversible inhibitor of sodium transport and blocks the Na+/H+ exchange pathway.
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.