title: Vascular effects of Physalia physalis venom in the skeletal muscle of the dog.
abstract: The purpose of this study was to characterize the mode of action of the venom from Portuguese man-of-war (Physalia physalis) on the skeletal muscle vascular bed of dogs anesthetized with sodium pentobarbital (35 mg/kg). Venous outflow and the blood pressure difference across the hind-limb vascular bed were used to calculate changes in resistance due to close arterial injections of the venom (0.001-1 microgram/kg). The venom consistently produced dilations that were blocked by sodium meclofenamate (5 mg/kg). Atropine (1 mg/kg), propranolol, phentolamine, cimetidine (each 2 mg/kg) or tripelennamine (2.5 mg/kg) had no significant blocking effect. The venom also produced transient dilations on vascular beds predilated with histamine or prostaglandin E1, or preconstricted with norepinephrine (each 0.01 microgram/kg) or by sympathetic stimulation (12 V, 20 Hz). These data suggest that Physalia venom dilates skeletal muscle vasculature primarily by stimulation of endogenous prostaglandin synthesis.
authors.forename: J S
authors.initials: JS
authors.lastname: Loredo
authors.forename: R R
authors.initials: RR
authors.lastname: Gonzalez
authors.forename: D A
authors.initials: DA
authors.lastname: Hessinger
mesh_terms: D000527:Alprostadil; D000818:Animals; D003064:Cnidarian Venoms / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004285:Dogs; D006632:Histamine / Q000097:blood; D008297:Male; D008469:Meclofenamic Acid / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009132:Muscles / Q000098:blood supply*; D009638:Norepinephrine / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
chemical_list: D003064:Cnidarian Venoms; D011458:Prostaglandins E; D008469:Meclofenamic Acid; D006632:Histamine; D000527:Alprostadil; D009638:Norepinephrine