Article Figures & Data
Figures
- Fig. 1.
Rat dorsal skin plasma extravasation caused by V. dubius venom. The rats were anesthetized with thiopental, the dorsal skin was shaved, and the animals received an i.v. injection of 125I-human serum albumin (2.5μCi/rat) with Evan's blue dye (25mg/kg). This was followed by the intradermal injection of vehicle (Tyrode) solution or venom (1–100 μg/site) in a fixed volume (100μl) using a random order and balanced site pattern. Thirty minutes later, the rats were euthanized, the dorsal skin was removed, and the injected sites were punched out and counted in a gamma counter to determine the extent of plasma extravasation (based on the accumulation of radiolabeled albumin). Plasma extravasation was expressed as the volume (μl) of plasma accumulated at each skin site. The columns represent the mean ± S.E.M. (n = 6). *P < 0.05 compared with vehicle (Tyrode) solution (column with 0 µg venom/site).
- Fig. 2.
The role of histamine, serotonin, bradykinin, and COX products in V. dubius (Vd) venom-induced plasma extravasation. The rats were prepared and treated as described in the legend for Fig. 1, except that prior to venom injection they received mepyramine (histamine H1 receptor antagonist; 6 mg/kg, i.p., 15 minutes before), cyproheptadine (dual serotonin 5-hydroxytryptamine1/2 and histamine H1 receptor antagonist; 2 mg/kg, i.p., 30 minutes before), JE 049 (B2 receptor antagonist; 0.6 mg/kg, i.v., 15 minutes before), or indomethacin (nonselective COX inhibitor; 10 mg/kg, i.p., 1 hour before). Subsequently, vehicle (Tyrode) solution, the respective positive control, and venom (10 µg/site) were injected intradermally in a fixed volume (100μl). Thirty minutes later, the rats were euthanized and processed, as described in Fig. 1. Plasma extravasation was expressed as the volume (μl) of plasma accumulated at each skin site. Histamine (His, 30 nmol/site), compound 48/80 (C48/80, 1 μg/site), and bradykinin (BK, 0,1 nmol/site?) were used as positive controls. The columns represent the mean ± S.E.M. (n = 6). *P < 0.05 compared with vehicle (Tyrode) solution and #P < 0.05 compared with the corresponding response to venom alone.
- Fig. 3.
Role of nitric oxide and neurokinins in V. dubius (Vd) venom-induced plasma extravasation. The rats were prepared and treated as described in the legend for Fig. 1, except that prior to venom injection they received (Upper panel) L-NAME (nitric oxide synthase inhibitor; 100 nmol/site) and (Lower panel) SR140333 (neurokinin NK1 receptor antagonist; 1 nmol/site) or SR48968 (neurokinin NK2 receptor antagonist; 0.3 µmol/kg, i.v.) that were coadministered with venom (10 µg/site) in a fixed volume (100μl). Thirty minutes later, the rats were euthanized and processed as described in Fig. 1. Plasma extravasation was expressed as the volume (μl) of plasma accumulated at each skin site. The columns represent the mean ± S.E.M. (n = 6). *P < 0.05 compared with vehicle (Tyrode) solution and #P < 0.05 compared with the corresponding response to venom alone.
- Fig. 4.
Attenuation of V. dubius venom-induced rat hind paw edema by ketoprofen (cyclooxygenase inhibitor; 20 mg/kg, i.p.) administered 15 minutes after venom. Rats were lightly anesthetized with isoflurane for venom injection in the subplantar region of the right hind paw. The paw volume was measured immediately before the injection of venom (20 μg/paw) or 0.9% NaCl (vehicle control) and at various intervals thereafter using a plethysmometer. The volume injected into the paws was always 100 μl. The increase in paw volume (ml) was calculated as the difference between the basal and final volumes. The points represent the mean ± S.E.M. (n = 6). All time points in the venom + saline and venom + ketoprofen groups were significantly different from the corresponding controls. *P < 0.05 compared with the corresponding times in the venom + saline group.
- Fig. 5.
Neutralization of V. dubius (Vd, 10 μg/site), P. nigriventer (Pn, 5 μg/site), and T. serrulatus (Ts, 5 μg/site) venom-induced plasma extravasation by IgG purified from antiarachnid antivenom. The venoms were incubated with IgG purified from antiarachnid antivenom (0.3 mg/ml for V. dubius and 0.1 mg/ml for P. nigriventer and T. serrulatus) for 1 hour at 37°C prior to testing in rat dorsal skin. The venom:IgG ratios used for these neutralization assays were 1:2 for P. nigriventer and T. serrulatus and 1:3 for V. dubius. Plasma extravasation was assessed by injecting venom and venom + antivenom IgG mixtures intradermally in the dorsal skin of anesthetized rats. Thirty minutes later, the rats were euthanized and processed, as described in Fig. 1. Plasma extravasation was expressed as the volume (μl) of plasma accumulated at each skin site. The columns represent the mean ± S.E.M. (n = 6). *P < 0.05 compared with vehicle (Tyrode) solution and #P < 0.05 compared with the corresponding response to venom alone.
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Vitalius dubius Venom-Induced Edema
