Molecular Characterization, Electrophysiological and Contraceptive Effect of Chilean Latrodectus Venom
Caracterización Molecular, Electrofisiológica y Efecto Anticonceptivo del Veneno de Latrodectus Chilena
Patricia Navarrete Gómez; *David Ormeño; **Antonio Miranda; Raúl Sánchez Gutiérrez; *,*****Fernando Romero Mejía & *Jorge ParodiRivera
NAVARRETE, G. P.; ORMEÑO, D.; MIRANDA, A.; SÁNCHEZ, G. R.; ROMERO, M. F. & PARODI, R. J. Molecular characterization, electrophysiological and contraceptive effect of Chilean Latrodectus venom. Int. J. Morphol., 29(3):733-741, 2011. SUMMARY: Since the 1970s, There have been studies of the venom of Latrodectus sp. spiders, in particular the latrotoxin (LTX) of Latrodectus mactans.Many of the studies were aimed at understanding the action of the venom on the muscular system. Now accepted that LTX is able to generate a calcium-permeable membrane pore and modulate the release of synaptic vesicles that activate a receptor and induce cellular changes. Interestingly, when work began with venom obtained from the Latrodectus sp present in Chile, it generated clinical indicationssimilar to the bite of this spider in another country, with some differences in intensity. The purpose of the first studies was to understand the systemic mechanisms of this venom, and other active compounds were studied for biological interest. It was found that these molecules are capable of causing systemic effects such as changes in muscle contraction; of generating vascular relaxation andsynaptic and cellular modulation; and of altering potassium conductance channels. Based on this evidence, we suggested biotechnological applications to characterize low molecular-weight compounds obtained from the Chilean Latrodectus venom and exploring the effects on the electrophysiology in oocytes and neurons, and the contraceptive effect on spermatozoa. KEY WORDS: Latrodectus venom; Oocytes;Neurons; Spermatozoa; Contraceptive.
The Chilean spider Latrodectus mactans (L. mactans) belongs to the Latrodectus genus which has worldwide distribution (Garb et al., 2004). It is known in Chile as "Araña del trigo" (wheat spider) or "black widow", and is present in various regions of the country. Its bite generates a systemic effect known as "latrodectism" or "systemicarachnoidism" in humans, in some cases causing death in both adults and children (Schenone & Correa, 1985). Venom collected from Chilean L. mactans in the VIII and IX Regions of Chile was shown to induce a sustained tonic effect in cardiac and smooth muscle (Romero et al., 2003). In smooth muscle, the mechanism of contraction is related to the permeability of sodium (Na+) and calcium (Ca ++) ions whichmodulate the contractile response (Nouailhetas et al., 1985) that has a fast, phasic component followed by a slower more sustained tonic component
(Shimuta et al., 1982). Our studies in the deferent vessel of the rat revealed that the effect induced by the L. mactans venom is partially dependent of adrenergic and cholinergic mediators (patent pending). Moreover, we tested the effect of Chilean venomin hippocampal neuron, and reported the changes in synaptic activity, for have synaptic effects under control and postulate, mechanism over neuromuscular union (Varghese et al., 2006). In a previous report we described that the venom of the Chilean black widow spider L. mactans increased intracellular calcium (Ca++i) concentration of the spermatozoa (Romero et al., 2007). Furthermore, this venomis known to block the tetraethylammonium (TEA)-sensitive potassium (K+) currents in neurons (Parodi & Romero, 2008;
*Center of Neurosciences and Peptides Biology- (CEBIOR), BIOREN, Universidad de La Frontera, Temuco, Chile. **Department of Biophysics University of Sao Paulo, Federal University of Sao Paulo, Sao Paulo, Brazil. ***Centre of Excellence in Biotechnology in Reproduction (CEBIOR),...