title: Synergism between hydrogen sulfide (H(2)S) and nitric oxide (NO) in vasorelaxation induced by stonustoxin (SNTX), a lethal and hypotensive protein factor isolated from stonefish Synanceja horrida venom.
abstract: Stonustoxin (SNTX) is a 148 kDa, dimeric, hypotensive and lethal protein factor isolated from the venom of the stonefish Synanceja horrida. SNTX (10-320 ng/ml) progressively causes relaxation of endothelium-intact, phenylephrine (PE)-precontracted rat thoracic aortic rings. The SNTX-induced vasorelaxation was inhibited by L-N(G)-nitro arginine methyl ester (L-NAME), suggesting that nitric oxide (NO) contributes to the SNTX-induced response. Interestingly, D, L-proparglyglycine (PAG) and beta-cyano-L-alanine (BCA), irreversible and competitive inhibitors of cystathionine-gamma-lyase (CSE) respectively, also inhibited SNTX-induced vasorelaxation, indicating that H(2)S may also play a part in the effect of SNTX. The combined use of L-NAME with PAG or BCA showed that H(2)S and NO act synergistically in effecting SNTX-induced vasorelaxation.
authors.affiliation: Department of Biochemistry, National University of Singapore, Blk MD4A, 10 Kent Ridge Crescent, Singapore.
authors.forename: H C
authors.initials: HC
authors.lastname: Liew
authors.forename: H E
authors.initials: HE
authors.lastname: Khoo
authors.forename: P K
authors.initials: PK
authors.lastname: Moore
authors.forename: M
authors.initials: M
authors.lastname: Bhatia
authors.forename: J
authors.initials: J
authors.lastname: Lu
authors.forename: S M
authors.initials: SM
authors.lastname: Moochhala
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism*; D003542:Cystathionine gamma-Lyase / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005397:Fish Venoms / Q000302:isolation & purification / Q000494:pharmacology*; D005400:Fishes, Poisonous; D006862:Hydrogen Sulfide / Q000819:agonists* / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000819:agonists* / Q000378:metabolism; D009924:Organ Culture Techniques; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D004791:Enzyme Inhibitors; D005397:Fish Venoms; D014662:Vasoconstrictor Agents; C073228:stonustoxin; D010656:Phenylephrine; D009569:Nitric Oxide; D003542:Cystathionine gamma-Lyase; D006862:Hydrogen Sulfide