LOCAL INFLAMMATORY EFFECTS EVOKED BY Polistes lanio lanio WASP VENOM IN THE MICE DORSAL SKIN: ROLE OF TACHYKININS

YSHII LM (1), HYSLOP S (2), BRAIN SD (3), TAM C (3), RIBELA MTP (4), MUSCARÁ MN (1); COSTA SKP (1)

(1) Dept. of Pharmacology, ICB-USP, São Paulo; (2) Dept. of Pharmacology, Unicamp, Campinas; (3) Cardiovascular Division, NHH, King's College London; (4) Ipen, São Paulo

Polistes lanio lanio wasp venom (PLLv) causes neurogenic oedema via a tachykinin NK1 receptor-mediated mechanism in mouse dorsal skin (1). Using venom obtained by a different extraction method, this effect was not inhibited by an NK1 receptor antagonist SR140333. We used normal C57BL/6 as well as NK1 and TRPV1 receptor knockout (KO) mice to compare the oedematogenic effects of venom prepared by these two methods. Venom (PLLv1) was obtained as described (1). In a new method, the venom sacs were removed along with the sting. The sting was inserted into a polyethylene cannula and the venom (PLLv2) was expelled into the cannula by lightly compressing the venom sac. Normal or NK1 and TRPV1 receptor KO mice (25-30 g) were anaesthetized with urethane. The venom or vehicle was injected i.d. into the shaved dorsal skin. After 30 min, the injected site was removed. Oedema formation was assessed by the extravascular accumulation of 125I-albumin in the skin compared to plasma. The results were expressed as the mean ± SEM and were compared by ANOVA plus Bonferroni’s test. Results show PLLv2 (0.3 – 10 mg/site) caused potent, dose-dependent oedema in mouse skin. In contrast to PLLv1, the PLLv2-induced effect was not affected by SR140333, but was markedly reduced by the histamine H1 receptor antagonist, pyrilamine. The PLLv2-induced oedema in normal mice was similar to that in NK1 and TRPV1 KO mice. We conclude that PLLv2 caused oedema more potent to that of PLLv1. In addition, the PLLv2 obtained by the new method was devoid of the neurogenic effect, suggesting that the previous method resulted in contamination of the venom by tachykinin-like components from glandular tissue.

KEY WORDS: Polistes, wasp, oedema, mice, TRPV1, NK1 receptor

1. YSHII LM, SOUZA GHMF, HYSLOP S et al. Proceed. Br Pharmacol Society. http://www.pa2online.org/abstracts/Vol3Issue4abst076P.pdf.

FINANCIAL SUPPORT: CAPES, CNPq, FAPESP, BHF (U.K.). M.A.A.G. Barreto provided technical help.

CORRESPONDENCE TO: S Costa. Dept of Pharmacology, ICB-USP. Phone/Fax: (+55) 11-30917320. E-mail: scosta@icb.usp.br Email: prianti@univap.br