Influence of cardiac rhythm disturbances and antiarrhythmic drugs on the efflux of PGE, PGF2α, cyclic AMP, and cyclic GMP in canine coronary sinus blood

In anaesthetized open-chest dogs, cardiac arrhythmias (CA) were induced by cumulative intravenous doses of aconitine or ouabain. Aconitine in a dose which did not induce CA had no influence on the PGE and PGF_2a effluxes into coronary sinus blood (CSB), whereas the PGE efflux into CSB increased after a subtoxic dose of ouabain. However, both PGE and PGF_2a effluxes were increased, when CA had developed. During aconitine induced CA, the PGE efflux was 6.5-fold and that of PGF_2a had increased by 80 %. During ouabain induced CA, the effluxes of both PGs were about 3-fold. Propranolol and lidocaine decreased the PGF_2α efflux into CSB by about 50 % and the PGE efflux was doubled after lidocaine and decreased after propranolol by about a third. The increased PGE efflux into CSB during CA was normalized after propranolol and quinidine if the CA was abolished or the cardiac rhythm improved. Lidocaine did not modify the increase in PGE efflux, despite the abolishment of CA. The increase in PGF_2α efflux was not influenced by antiarrhythmic drugs. The cyclic AMP and cyclic GMP in CSB remained unchanged during ouabain induced arrhythmias or after propranolol. The increased efflux of PGE into CSB during aconitine and ouabain induced CA and its abolishment by propranolol support the hypothesis that PGE participates in the modulation of increased sympathetic tone during CA.