Excitation and inhibition by cisapride of spontaneous and evoked electrical responses in smooth muscles of guinea-pig stomach.
In isolated circular smooth muscles of the guinea-pig stomach, cisapride depolarized the membrane, increased the amplitude and interval of slow waves, and enhanced the cholinergic excitatory junction potential, with no change in the nonadrenergic noncholinergic inhibitory junction potentials. Methysergide mimicked the excitatory actions of cisapride on junction potentials. Results showed that cisapride has dual actions on gastric muscles; excitation by facilitating the release of ACh possibly via 5-HT receptor blockade and also by depolarizing the smooth muscle membrane, and inhibition by reducing the frequency of slow waves, possibly by acting directly on the pacemakers.
Ohno
N
N
Department of Physiology, Nagoya City University Medical School, Japan.
Zhang
G
G
Xue
L
L
Yamamoto
Y
Y
Itoh
M
M
Suzuki
H
H
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D020117:Cisapride; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008784:Methysergide / Q000494:pharmacology; D008839:Microelectrodes; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D009469:Neuromuscular Junction / Q000187:drug effects; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D010276:Parasympatholytics / Q000494:pharmacology; D010277:Parasympathomimetics / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects* / Q000294:innervation / Q000502:physiology
D010276:Parasympatholytics; D010277:Parasympathomimetics; D010880:Piperidines; D012702:Serotonin Antagonists; D001285:Atropine; D000109:Acetylcholine; D020117:Cisapride; D008784:Methysergide