Abstract
Venom (10 microg/ml) relaxed phenylephrine-precontracted aortae. This relaxation was unaffected by removal of the endothelium or a combination of N(G)-nitro-L-arginine (L-NOARG; 0.1 mM), oxyhaemoglobin (10 microM) and indomethacin (10 microM). 4-BPB (0.78 mM), propranolol (1 microM), or a combination of apamin (0.1 microM), charybdotoxin (0.1 microM) and glibenclamide (10 microM) did not effect endothelium-independent relaxation, suggesting a lack of PLA2 activity or an effect at beta-adrenoceptors or K+ channels. Venom (10 microg/ml) reversed Bay K 8644 (0.1 microM)-induced contraction indicating the venom may have an effect on L-type Ca2+ channels.
MeSH terms
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3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology
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Animals
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Aorta, Thoracic / drug effects
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Elapid Venoms / toxicity*
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In Vitro Techniques
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Male
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Muscle Contraction / drug effects
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Muscle Relaxation / drug effects
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Muscle, Smooth / drug effects*
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Phenylephrine / antagonists & inhibitors
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Phenylephrine / pharmacology
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Rats
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Rats, Sprague-Dawley
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Vasoconstrictor Agents / antagonists & inhibitors
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Vasoconstrictor Agents / pharmacology
Substances
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Elapid Venoms
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Vasoconstrictor Agents
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Phenylephrine
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3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester