[4-Aminopyridine induced histamine release and its antagonism by certain drugs].
4-Aminopyridine (4-AP), a known potassium channel blocker, was shown to induce histamine release from mast cells in mice. After ip 4-AP 5 mg.kg-1 the histamine content increased in blood, but decreased in the lung tissue. Calcium antagonists nifedipine (NIF) 500 mg.kg-1 ig, TMB-8 300 mumol.L-1 in vitro and potassium channel opener minoxidil (MIN) 100 mg.kg-1 inhibited the histamine release induced by 4-AP from mouse peritoneal mast cells (PMC). These results provide evidence that potassium channels are present in mouse mast cell membranes and indicate that the mechanism of histamine release by 4-AP may be related to the potassium channel blocking effect. As the result of this effect, the calcium channels open and the Ca2+ influx to the mast cells increases, thus eliciting histamine release.
Xu
J H
JH
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Zhejiang Medical University, Hangzhou.
Wu
H S
HS
Li
L
L
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005260:Female; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006632:Histamine / Q000378:metabolism; D006636:Histamine Release / Q000187:drug effects*; D008168:Lung / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000378:metabolism; D051379:Mice; D008914:Minoxidil / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology
D002121:Calcium Channel Blockers; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D008914:Minoxidil; D005707:Gallic Acid; D006632:Histamine; D015761:4-Aminopyridine; D009543:Nifedipine