Nitric oxide causes contraction in the rat isolated small intestine.
The effect of authentic nitric oxide (NO) was investigated on rat ileal myenteric plexus-longitudinal muscle strips in the presence of atropine. NO (10(-10) to 3 x 10(-6) M) caused a quick, transient contraction of the smooth muscle, with an optimum concentration of 10(-7) M, as well as a slower contraction with a higher optimum concentration. In preparations sub-maximally pre-contracted with 5-hydroxytryptamine, NO (10(-7) to 3 x 10(-6) M) also caused a quick relaxant response. These responses to NO (10(-6) M) were not influenced by tetrodotoxin, indicating a direct effect on the smooth muscle.
Department of Pharmacology, University Medical School Pécs, Hungary.
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Barthó
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Lefebvre
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009569:Nitric Oxide / Q000494:pharmacology*; D019335:Nitroarginine; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D019335:Nitroarginine; D009569:Nitric Oxide; D012701:Serotonin; D013779:Tetrodotoxin; D001120:Arginine