Atrial natriuretic peptide effect on NADPH-diaphorase in rat intestinal

L.V. GONZA´LEZ BOSCA,C,*, F. CAPANID, J.J. LO´PEZ–COSTAD, M.C. ORTIZA,C, M.P. MAJOWICZA,C,M.A. COSTAB,C, C.T. ARRANZB,C, A.M. BALASZCZUKB,C, J. PECCI SAAVEDRAD, N.A. VIDALA,C

Peptide

Año: 1999 vol. 20 p. 615 - 621

Histochemical reaction of NADPH-diaphorase (NOS-NADPH-d) was used to identify NO synthesis. A 30-min 0.1 mg/kg/min ANP infusion led to about a 10% and 35% increase in small and large intestine enterocytes stain respectively. This increase was abolished bya bolus of 1 mg/kg L-NAME before ANP infusion in small intestine, and partially abolished it in colon. Incubation of small and largeintestine with 0.5 mM 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 thatANP enhances NOS-NADPH-d activity, suggesting that ANP stimulates NO synthase in enterocytes by L-arginine-NO pathway. 8-BrcGMPmimicked the effect of ANP described above. Therefore, the guanylate cyclase-coupled natriuretic receptors, NPR-A and NPR-B,probably mediate this ANP effect.mg/kg/min ANP infusion led to about a 10% and 35% increase in small and large intestine enterocytes stain respectively. This increase was abolished bya bolus of 1 mg/kg L-NAME before ANP infusion in small intestine, and partially abolished it in colon. Incubation of small and largeintestine with 0.5 mM 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 thatANP enhances NOS-NADPH-d activity, suggesting that ANP stimulates NO synthase in enterocytes by L-arginine-NO pathway. 8-BrcGMPmimicked the effect of ANP described above. Therefore, the guanylate cyclase-coupled natriuretic receptors, NPR-A and NPR-B,probably mediate this ANP effect.