Contrasting effects of tetraethylammonium and 4-aminopyridine on the gastrointestinal function of mice.
Many different K+ channels have been identified in the gastrointestinal tract, and the two classical K+ channel blockers, tetraethylammonium and 4-aminopyridine, show different sensitivity for these channels. The aim of the present study was to compare the effects of tetraethylammonium and 4-aminopyridine on the gastrointestinal function of mice. 4-Aminopyridine (5 mg/kg, p.o.) inhibited, but tetraethylammonium (40 mg/kg, p.o.) enhanced, the intestinal propulsion of a charcoal suspension in conscious mice. Studies in vitro showed that perfusion of 5 mM 4-aminopyridine increased the maximal contractile force and minimal relaxation force, and decreased the amplitude and frequency of the peristaltic contraction of the isolated duodenum. However, perfusion of 5 mM tetraethylammonium increased the maximal contractile force, the minimal relaxation force and the amplitude of the contraction. The effects of tetraethylammonium and 4-aminopyridine on the duodenal contraction could be abolished completely by application of 5 microM verapamil. Our results in vivo and in vitro showed that tetraethylammonium and 4-aminopyridine had contrasting effects on the gastrointestinal function of mice.
Dong
De-Li
DL
Department of Pharmacology, Harbin Medical University; Bio-pharmaceutical Key Laboratory, Baojian Road 157, Harbin 150086, Heilongjiang Province, China. delidong2004@yahoo.com.cn
Wang
Qing-Hui
QH
Chen
Wei
W
Fan
Jiao-Jie
JJ
Mu
Jing-Wei
JW
Ke
Jia
J
Yang
Bao-Feng
BF
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D004386:Duodenum / Q000187:drug effects / Q000502:physiology; D005744:Gastric Acid / Q000378:metabolism; D005748:Gastric Fundus / Q000187:drug effects / Q000502:physiology; D005753:Gastric Mucosa / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000187:drug effects; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000502:physiology; D005772:Gastrointestinal Transit / Q000187:drug effects; D066298:In Vitro Techniques; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013270:Stomach / Q000187:drug effects; D019789:Tetraethylammonium / Q000494:pharmacology*
D026902:Potassium Channel Blockers; D019789:Tetraethylammonium; D015761:4-Aminopyridine