Renal- and calcium-dependent vascular effects of Polybia paulista wasp venom

Vinhote JFC (1), Torres AFC (2), Dantas RT (1), Praciano TP (2), Menezes RRPPB (1), Sousa DF (1), Brito TS (1), Lima FJB (1), Toyama MH (3), Magalhães PJ (1), Monteiro HSA (1), Martins-Nunes AMC (2)

(1) Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, Ceará State, Brazil; (2) Department of Clinical and Toxicological Analyses, Federal University of Ceará, Fortaleza, Ceará State, Brasil; (3) São Paulo Experimental Coast Campus, São Paulo State University (UNESP - Univ Estadual Paulista), São Vicente, São Paulo State, Brazil.

Abstract: In the present study, the effects of Polybia paulista venom (PPV) on renal and vascular tissues were investigated. Isolated kidneys perfused with PPV (1 and 3 µg/mL) had increased perfusion pressure, renal vascular resistance, urinary flow, and glomerular filtration rate; and reduced sodium tubular transport. Histological evaluation demonstrated deposits of proteins in Bowman’s space and tubular lumen, and focal areas of necrosis. The venom promoted a cytotoxic effect on Madin-Darby canine kidney (MDCK) cells. A significant increase in lactic dehydrogenase levels was observed in response to venom exposure. In isolated mesenteric vascular beds, pressure and vascular resistance augmented in a dose-dependent manner. PPV increased the contractility of aortic rings maintained under basal tension. This contractile response was inhibited when preparations were maintained in Ca2+-free medium. Likewise, verapamil, a voltage-gated calcium channel blocker, also inhibited the contractile response. In this study, phentolamine, a blocker of α-adrenergic receptor blocker, significantly reduced the contractile effect of PPV in the aortic ring. In conclusion, PPV produced nephrotoxicity, which suggests a direct effect on necrotic cellular death in renal tubule cells. The vascular contractile effect of PPV appears to involve calcium influx through voltage-gated calcium channels via adrenergic regulation.

Key words: Polybia paulista, venom, kidney, aorta, MDCK.

ACKNOWLEDGEMENTS

The authors thank Aline Falcão for the technical assistance, and The National Council for Scientific and Technological Development (CNPq) and The Cearense Foundation for Supporting Scientific and Technological Development (FUNCAP) for supporting the research.

COPYRIGHT

© CEVAP 2011

SUBMISSION STATUS

Received: February 7, 2011.

Accepted: April 1, 2011.

Abstract published online: April 6, 2011.

Full paper published online: May 31, 2011.

CONFLICTS OF INTEREST

There is no conflict.

FINANCIAL SOURCE

CNPq and FUNCAP provided the financial grants.

ETHICS COMMITTEE APPROVAL

All experiments were in accordance with the guidelines for the ethical use of experimental animals published by the Brazilian College on Experimental Animal Care (COBEA). Moreover, the present study was approved by the Institutional Animal Care Committee at Federal University of Ceará (protocol number 17/09).

CORRESPONDENCE TO

ALICE MARIA COSTA MARTINS NUNES, Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, CE, 60.420-970, Brasil. Phone: +55 85 3366 8263. Fax: +55 85 3366 8292. Email: martinsalice@gmail.com.