title: Potentiation of neostigmine and pyridostigmine by 4-aminopyridine in the rat.
abstract: The interaction between 4-aminopyridine and neostigmine or pyridostigmine was studied in vivo in the rat sciatic nerve-anterior tibialis preparation using the constant infusion of pancuronium technique. The ED50 (dose of drug which produced a 50% antagonism) of neostigmine, pyridostigmine and 4-aminopyridine were 18, 49 and 440 microgram kg(-1) respectively. The addition of 100 microgram kg(-1) of 4-aminopyridine, which produced no antagonism by itself, decreased the neostigmine ED50 to 7.4 microgram kg(-1). The addition of 200 microgram kg(-1) of 4-aminopyridine, which produced a 30% antagonism by itself, decreased the ED50 of pyridostigmine to 11 microgram kg(-1). We conclude that both neostigmine and pyridostigmine interact with 4-aminopyrine synergistically.
mesh_terms: D000631:Aminopyridines / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D009119:Muscle Contraction / Q000187:drug effects; D009388:Neostigmine / Q000494:pharmacology*; D010197:Pancuronium / Q000037:antagonists & inhibitors; D011729:Pyridostigmine Bromide / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
chemical_list: D000631:Aminopyridines; D009388:Neostigmine; D010197:Pancuronium; D011729:Pyridostigmine Bromide