Dual effects of trimebutine on electrical responses of gastric smooth muscles in the rat.
The effects of trimebutine on the electrical properties of smooth muscle membranes were studied in the isolated rat stomach, the objective being to elucidate the dual actions of this drug on gastric motility. Transmural nerve stimulation elicited a cholinergic excitatory junction potential (e.j.p.) and a nonadrenergic noncholinergic inhibitory junction potential (i.j.p.), and trimebutine inhibited the e.j.p. more than the i.j.p., with no significant change in the acetylcholine-induced depolarization. Trimebutine reduced the interval and, at high concentrations, the amplitude of slow waves. In enzymatically dispersed single cells, the Ca2+ current elicited by depolarization of the membrane was also inhibited by trimebutine. Thus, trimebutine increases slow wave frequency and inhibits cholinergic transmission and Ca2+ influx. The former would enhance while the latter two would depress gastric motility.
Xue
L
L
Department of Physiology, Nagoya City University Medical School, Japan.
Fukuta
H
H
Yamamoto
Y
Y
Suzuki
H
H
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation; D004594:Electrophysiology; D005769:Gastrointestinal Motility / Q000187:drug effects; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008839:Microelectrodes; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D009469:Neuromuscular Junction / Q000187:drug effects; D010275:Parasympathetic Nervous System / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D013270:Stomach / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D014287:Trimebutine / Q000494:pharmacology*
D015220:Calcium Channels; D010276:Parasympatholytics; D014287:Trimebutine