[The anti-arrhythmia and pro-arrhythmia properties of sigma-receptor ligands]

It has been found that the sigma 1- and sigma 3-receptor antagonists, DuP 734 intraperitoneally and XJ 448 intravenously, had antiarrhythmic effects against epinephrine-induced arrhythmias in rats. The ED50 for antiarrhythmic effect of DuP 734 was 0.157 mg/kg after intraperitoneal administration. Other sigma-receptor antagonists (rimcazole, BMY 14802, haloperidol) did not affect the incidence of epinephrine-induced arrhythmias. sigma 1-Receptor agonists (DTG, N-allyl-normetazocine, (+)-3-PPP, (-)-3-PPP) had proarrhythmic effect after systemic administration. The sigma-agonist N-allyl-normetazocine and sigma-antagonist XJ 488 had no effect on the incidence of epinephrine-induced arrhythmias after intracerebroventricular administration. Therefore, it appears that the central nervous system does not play a significant role in the antiarrhythmic or proarrhythmic effects of sigma ligands. We hypothesize that these effects of sigma ligands might be dependent on their action on cardiac sigma receptors.