Abstract
Histochemical reaction of NADPH-diaphorase (NOS-NADPH-d) was used to identify NO synthesis. A 30-min 0.1 microg microg/kg/min ANP infusion led to about a 10% and 35% increase in small and large intestine enterocytes stain respectively. This increase was abolished by a bolus of 1 mg/kg L-NAME before ANP infusion in small intestine, and partially abolished it in colon. Incubation of small and large intestine with 0.5 microM ANP increased stain at about 20%. In both tissues the preincubation with 0.1 mM L-NAME abolished the ANP effect. Incubation with 0.1 mM 8-Br-cGMP enhanced staining about 70% and 30% in small and large intestine respectively. Our results show that ANP enhances NOS-NADPH-d activity, suggesting that ANP stimulates NO synthase in enterocytes by L-arginine-NO pathway. 8-Br-cGMP mimicked the effect of ANP described above. Therefore, the guanylate cyclase-coupled natriuretic receptors, NPR-A and NPR-B, probably mediate this ANP effect.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Atrial Natriuretic Factor / pharmacology*
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Colon / cytology
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Colon / drug effects
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Colon / enzymology
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Cyclic GMP / analogs & derivatives
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Cyclic GMP / pharmacology
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Guanylate Cyclase / metabolism
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Histocytochemistry
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Image Processing, Computer-Assisted
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Intestinal Mucosa / cytology
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Intestinal Mucosa / drug effects*
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Intestinal Mucosa / enzymology
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Intestine, Small / cytology
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Intestine, Small / drug effects
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Intestine, Small / enzymology
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Isoenzymes
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Male
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NADPH Dehydrogenase / analysis*
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NG-Nitroarginine Methyl Ester / pharmacology
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Nitric Oxide / biosynthesis*
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Nitric Oxide Synthase
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Photoperiod
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Rats
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Rats, Wistar
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Receptors, Atrial Natriuretic Factor / metabolism
Substances
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Isoenzymes
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8-bromocyclic GMP
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Nitric Oxide
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Atrial Natriuretic Factor
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Nitric Oxide Synthase
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NADPH Dehydrogenase
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Guanylate Cyclase
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Receptors, Atrial Natriuretic Factor
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atrial natriuretic factor receptor A
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atrial natriuretic factor receptor B
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Cyclic GMP
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NG-Nitroarginine Methyl Ester