Excitation of autonomic nerves by 4-aminopyridine in the isolated, blood-perfused sino-atrial node preparation of the dog.
4-Aminopyridine injected into the sinus node artery produced a long-lasting decrease in sinus rate preceded by a transient increase. With a large dose, a long-lasting increase in sinus rate was superimposed on the long-lasting decrease phase. The long-lasting decrease and increase in sinus rate were abolished by 1-hyoscyamine and propranolol respectively, and both were reduced by tetrodotoxin. These results can be interpreted as being due to excitation of autonomic nerves by 4-aminopyridine.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000187:drug effects*; D004285:Dogs; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008688:Methacholine Compounds / Q000494:pharmacology; D009538:Nicotine; D011433:Propranolol / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*; D012849:Sinoatrial Node / Q000502:physiology*; D013268:Stimulation, Chemical; D013779:Tetrodotoxin / Q000494:pharmacology
D008688:Methacholine Compounds; D011725:Pyridines; D013779:Tetrodotoxin; D009538:Nicotine; D001285:Atropine; D011433:Propranolol; D007545:Isoproterenol