, 2000 and Sollod et al., 2005). Although the major toxins of spider venoms are neurotoxic peptides, which act on a vast array of ion channels ( Kushmerick et al., 1999, Escoubas et al., 2000, Gomez et al., 2002, Matavel et al., 2002 and King and Hardy, 2013), non-neurotoxic peptides and also non-peptidic molecules have been described ( Bento et al., 1993, Marangoni et al., 1993, Rego et al.,

1996 and Rash and Hodgson, 2002). Lasiodora spiders are members of Theraphosidae family (suborder Mygalomorphae). They are commonly known in Brazil as caranguejeiras. The different species of Lasiodora spiders are difficult to distinguish ( Brazil and Vellard, 1926). These spiders, as predators, use their venom to feed on a variety of both vertebrate and invertebrate prey. Moreover, the ability to paralyze higher vertebrates makes the venoms of all mygalomorph spiders intriguing sources of compounds for Rucaparib the study Venetoclax of various receptors in vertebrates

( Escoubas and Rash, 2004). Reports on bites in humans caused by mygalomorph spiders are rare. The clinical symptoms observed after the bite are local pain, edema and erythema (Lucas et al., 1994 and Isbister et al., 2003). Lasiodora sp. spider venom has not been systematically studied. However, even venoms with low human toxicity can be sources for interesting physiological research ( Escoubas crotamiton and Rash, 2004). We have previously described that Lasiodora sp. crude venom inhibits L-type Ca2+ channels (Cav1) and modulates the activity of Na+ channel in GH3 cells ( Kushmerick et al., 2001). Vieira et al. (2004) identified three toxins expressed by the Lasiodora sp. venom gland. These toxins, named LTx1, LTx2 and LTx3, showed significant similarity with other toxins from Lasiodora parahybana, Eurypelma californicum, Brachypelma smithii and Selenocosmia huwena spider venoms. Dutra et al. (2008) observed that recombinant LTx2 blocks Cav1 channels in BC3H1 cells.

Our research group has also described the action of Lasiodora sp. venom on the isolated rat heart. This venom caused concentration-dependent bradycardia, with transient cardiac arrest and rhythm disturbances. Therefore, the authors suggested that Lasiodora crude venom evokes vesicular release of acetylcholine from parasympathetic nerve terminals by activating tetrodotoxin-resistant Na+ channels ( Kalapothakis et al., 2003). Thus, Lasiodora sp. venom may be a potential source of active toxins in various physiological systems, including the cardiovascular system. Many venom components, including bradykinin-potentiating peptides, sarafotoxins, and natriuretic peptides have significant cardiovascular effects ( Hodgson and Isbister, 2009 and Camargo et al., 2012). The aim of the present work was to characterize the pharmacological action of Lasiodora sp.