Endothelium-Dependent Relaxation of Rat Mesenteric Arterial Rings by a Phoneutria nigriventer Venom Fraction

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概要

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• Phoneutria nigriventer spider venom has been described as acting on several cardiovascular sites. In the present paper, a semi-purified fraction of this spider venom was studied to observe any contractile or relaxing effect in rat mesenteric arterial rings (MAR). Spider venom was first fractionated by gel filtration and subsequently by gradual isocratic steps in 0.1% trifluoroacetic acid. The first fraction of this last fractionation step is studied in the present paper and due to its main effect, it was named NORF (nitric oxide releasing fraction). No direct contractile effect was induced by NORF in relaxed MAR, suggesting no NORF-induced neurotransmitter release in this preparation. No significant influence of NORF was observed on concentration-response curves to phenylephrine on endothelium-denuded MAR, but a significant inhibitory shift of concentration-respense curves was observed on endothelium-preserved MAR (EC50 = 0.39 ± 0.07 μM for control and EC50 = 0.68 ± 0.14 μM with NORF). NORF induced concentration-dependent relaxation in endothelium-preserved phenylephrine pre-contracted MAR but not in endothelium-denuded MAR. NORF-induced relaxation was inhibited by the nitric oxide synthase inhibitor <sc>L</sc>-NAME (Nω-nitro-arginine methyl ester). Indomethacin or HOE-140 (<sc>D</sc>-Arg-[Hyp3,Thi5,<sc>D</sc>-Tic7,Oic8]-bradykinin) had no significant effect on NORF-induced relaxation. Acetylcholine-and NORF-induced relaxation of pre-contracted MAR were differently inhibited by atropine. The pA2 value for atropine-acetylcholine was 9.78 ± 0.06 and that for atropine-NORF was 8.53 ± 0.30 (P<0.01). These observations suggest that NORF induces concentration-dependent liberation of nitric oxide from MAR endothelium and that a non-muscarinic mechanism might be involved in this effect. Our data suggest no involvement of prostanoids or bradykinin in the relaxing mechanism.

• 社団法人 日本薬理学会の論文
• 2002-02-01

著者

• De Lima

  Venom And Toxin Laboratory Department Of Bioichemistry; Universidade Federal De Minas Gerais

• Cordeiro Marta

  Research And Developing Center Fundacao Ezequiel Dias

• Weinberg Maria

  Vascular Smooth Muscle Laboratory Department Of Physiology And Biophysics; Universidade Federal De M

• OLIVEIRA Leida

  Research and Developing Center, Fundacao Ezequiel Dias

• DINIZ Carlos

  Research and Developing Center, Fundacao Ezequiel Dias

• Oliveira Leida

  Research And Developing Center Fundacao Ezequiel Dias

• Diniz Carlos

  Research And Developing Center Fundacao Ezequiel Dias

• Weinberg Maria

  Vascular Smooth Muscle Laboratory Department Of Physiology And Biophysics Icb Federal University Of

関連論文

• Endothelium-Dependent Relaxation of Rat Mesenteric Arterial Rings by a Phoneutria nigriventer Venom Fraction
• Biochemical Properties of a Bushmaster Snake Venom Serine Proteinase (LV-Ka), and Its Kinin Releasing Activity Evaluated in Rat Mesenteric Arterial Rings
• Biochemical Properties of a Bushmaster Snake Venom Serine Proteinase (LV-Ka), and Its Kinin Releasing Activity Evaluated in Rat Mesenteric Arterial Rings

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