The vagal involvement in the antiarrhythmic and arrhythmogenic effects of prostaglandin F2 alpha on ouabain-induced cardiac arrhythmias in cats.

The effects of prostaglandin F2 alpha (PGF2 alpha) on ouabain-induced cardiac arrhythmias were investigated in chloralose-anaesthetized cats. Bilateral vagotomy and atropine intervention were employed to elucidate the involvement of vagal neural influences. PGF2 alpha (2-16 micrograms/kg i.v. bolus) predominantly suppressed the ouabain-induced ventricular and supraventricular arrhythmias and less commonly aggravated them in vagi-intact cats. The antiarrhythmic effect of PGF2 alpha was considerably, but not statistically significantly, decreased while its arrhythmogenic effect was significantly (p less than 0.05) increased in atropine-pretreated group. In vagotomised group PGF2 alpha failed to abolish the arrhythmias but it aggravated them to a degree comparable to that observed in vagi-intact group. It is concluded that the PGF2 alpha exhibits both antiarrhythmic and arrhythmogenic properties and these are largely due to elicitation of two opposing neural reflexes - one being protective and another being deleterious to ouabain-induced arrhythmias.