In this study, we report for the first LBH589 research buy time the vasodilator activity of Lasiodora sp. venom, which is dependent on endothelial nitric oxide (NO). Furthermore, we used assay-directed fractionation protocols, mass spectrometry (MS) and nuclear magnetic resonance (NMR) analysis to isolate and identify one main vasoactive molecule from

Lasiodora sp. venom: adenosine diphosphate (ADP). The drugs used were all purchased from Sigma-Aldrich (St. Louis, MO, USA). Indomethacin was dissolved in 0.5% w/v sodium bicarbonate. The other compounds were dissolved in distilled water. For isolated aorta protocols, drugs were diluted in Krebs-Henseleit solution before the experiments. Lasiodora specimens were from the city of Uberlândia in the state of Minas Gerais, Brazil. A voucher specimen of the spider under study has been deposited as collection number IBSP 8539 in the Instituto Butantan, located in São Paulo, Brazil. Lasiodora venom was obtained by electrical shock of the chelicerae using a custom stimulator, which included a guard to avoid contamination of the venom by regurgitated stomach contents.

After extraction, the venom was stored immediately at −20 °C. Protein concentration in the venom was measured as described by Bradford (1976). Male Wistar rats (210-300 g) from the Animal Care facilities (CEBIO) at the Federal University of Minas Gerais (UFMG) Veliparib nmr were used. They were kept at 22-25 °C in a 12 h light/dark cycle, and had free access to food and water. Animal experiments were performed according to the recommendations of the Brazilian Council for Animal Care and were approved by the Ethics Committee (protocols 166/07 and 234/12 CETEA) of UFMG. This protocol was performed as described by Cruz et al. (2006).

Male Wistar rats were decapitated and exsanguinated. The descending thoracic aorta was excised, free of fat and connective tissue, cut into rings about 4-5 mm in length and set up in an organ chamber containing Krebs-Henseleit solution [(mM): NaCl, 110.8; KCl, 5.9; NaHCO3, 25.0; MgSO4, 1.07; CaCl2, 2.49; NaH2PO4, 2.33; glucose, Florfenicol 11.51]. When necessary, the endothelium was removed mechanically by gently rubbing the intimal surface. The tissues were constantly gassed with a carbogenic mixture (95% O2 and 5% CO2), maintained at 37 °C under a tension of 1 g, and equilibrated for 1 h before initiating experimental protocols. During this period, the incubation solution was changed every 15 min. After the equilibration period, the presence of functional endothelium was assessed by the ability of acetylcholine (10 μM) to induce more than 80% relaxation of vessels pre-contracted with phenylephrine (0.3 μM). The absence of functional endothelium was confirmed by the lack of a relaxation response to acetylcholine in aortic rings pre-contracted with phenylephrine.