Pardaxin produces postjunctional muscle contraction in guinea-pig intestinal smooth muscle

British Journal of Pharmacology
N Primor


The action of pardaxin (PX), a toxin isolated from the secretion of the Red Sea flatfish, Pardachirus marmoratus, was studied on longitudinal muscle of guinea-pig ileum. Pardaxin contracted the ileum and subsequently abolished muscle contraction to 5-hydroxytryptamine (5-HT), but did not affect the responses to acetylcholine (ACh) and substance P(SP). Pardaxin-induced contraction was only partially suppressed by atropine and not affected by tetrodotoxin or morphine. Preparations desensitized to 5-HT or SP responded normally to pardaxin. Pardaxin-induced contractions were normal in K+-depolarizing Krebs Ringer solution and not affected by black widow spider venom. It is concluded that the pardaxin-induced muscle contractions are not mediated through the release of neurotransmitters and do not involve 5-HT, SP or ACh receptors, but are due to a direct action on the muscle contractile mechanism.


Jan 1, 1976·Toxicon : Official Journal of the International Society on Toxinology·J Parness, E Zlotkin
Sep 1, 1974·The Journal of Pharmacy and Pharmacology·V F Einhorn, R C Hamilton
Jul 1, 1972·The Journal of Pharmacy and Pharmacology·B Cox, D M Lomas
Jun 16, 1982·European Journal of Pharmacology·J P Huidobro-ToroJ M Musacchio
Jan 1, 1981·Toxicon : Official Journal of the International Society on Toxinology·N Primor, P Lazarovici
Jan 1, 1982·Transactions of the Royal Society of Tropical Medicine and Hygiene·R C Thompson, L M Kumaratilake
Dec 16, 1980·Biochimica Et Biophysica Acta·N Primor, A T Tu

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