4-Aminopyridine on the spontaneous contractions of isolated intestine.
The effects of 4-aminopyridine on isolated spontaneously active segments of rabbit jejunum were studied. The drug produced a dose-dependent increase of the tonic and phasic components of the contractile activity with an ED50 of 2 x 10(-5) M, lower than the reported dose for striated muscle. No effects were observed on the frequency of contractions at the concentrations of 4-aminopyridine used in this study. The results suggest both, an effect on the jejunal innervation and a direct action of the drug on the intestinal smooth muscle. The former mechanism includes the release of acetylcholine and is partially blocked by atropine. Direct effects of 4-aminopyridine on intestinal smooth muscle cells can be present at relatively low doses and they must be carefully evaluated during the suggested therapy of several human diseases with 4-aminopyridine.
Gónzalez
D
D
Morales-Aguilera
A
A
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007583:Jejunum / Q000187:drug effects*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D009388:Neostigmine / Q000494:pharmacology; D011817:Rabbits; D013268:Stimulation, Chemical
D009388:Neostigmine; D001285:Atropine; D015761:4-Aminopyridine