The failure of pyridostigmine to influence the coronary artery spasms induced by vasopressin in conscious rabbits

Abstract In conscious rabbits the intravenous (IV) injection of vasopressin (1 IU/kg IV) induced a coronarocostrictor effect and an increase in S-T segment and T wave amplitude. These changes were accompanied by sinus bradycardia and cardiac arrythmias. The injection of pyridostigmina (250 μg/kg), a reversible cholinesterase inhibitor with predominant muscarinic effects, failed to antagonize the coronarocostrictor effect of vasopressin, as judged by the changes in electrocardiographic recordings.