The smooth muscle relaxant effects of venom from the inland taipan (Oxyuranus microlepidotus)

Toxicon. 1999 Jan;37(1):229-31. doi: 10.1016/s0041-0101(98)00167-6.

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

  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology
  • Animals
  • Aorta, Thoracic / drug effects
  • Elapid Venoms / toxicity*
  • In Vitro Techniques
  • Male
  • Muscle Contraction / drug effects
  • Muscle Relaxation / drug effects
  • Muscle, Smooth / drug effects*
  • Phenylephrine / antagonists & inhibitors
  • Phenylephrine / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Vasoconstrictor Agents / antagonists & inhibitors
  • Vasoconstrictor Agents / pharmacology

Substances

  • Elapid Venoms
  • Vasoconstrictor Agents
  • Phenylephrine
  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester