Molecular characterization, electrophysiological and contraceptive effect of chilean latrodectus venom / Caracterización molecular, electrofisiológica y efecto anticonceptivo del veneno de latrodectus chilena

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 indications similar 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 and synaptic 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.

Desde los años 70, se han realizado estudios con el veneno de arañas Latrodectus sp, en particular la latrotoxina (LTX) de Latrodectus mactans. Muchos de estos estudios estuvieron enfocados a entender la acción del veneno sobre el sistema muscular. Hoy en día es aceptado que la LTX es capaz de generar un poro de membrana permeable a calcio y modular la liberación de vesículas sinápticas que activan un receptor e inducen cambios celulares. Interesantemente, cuando comenzamos a trabajar con el veneno obtenido de Latrodectus sp. presente en Chile, ésto generó indicaciones clínicas similares a la picadura de esta araña en otros países, con algunas diferencias en su intensidad. El propósito de estos primeros estudios fue entender los mecanismos sistémicos de este veneno y además otros compuestos activos fueron estudiados para interés biológico. Se ha encontrado que estas moléculas son capaces de causar efectos sistémicos así como cambios en la contracción muscular; generar relajación vascular y modulación sináptica y celular; y de alterar los canales de conductancia de potasio. Basados en estas evidencias, nosotros sugerimos usar aplicaciones biotecnológicas para caracterizar los compuestos de bajo peso molecular obtenidos del veneno de Latrodectus Chilena y explorar los efectos sobre la electrofisiología en ovocitos y neuronas, y el efecto anticonceptivo sobre los espermatozoides.

Production of TNF-alfa by primary cultures of human keratinocytes challenged with Loxosceles gaucho venom

Culturas primarias de queratinocitos humanos foram incubadas com veneno de aranha Loxosceles gaucho, que possui atividades esfingomielinase D, responsavel por lesao dermo-necrotica nos acidentes humanos. As celulas das culturas primarias foram agredidas com o veneno em doses crescentes de 10 ng/mL a 2 ug/mL. No sobrenadante das culturas...

Effect of Phoneutria nigriventer spider venom on gastric emptying in rats

The effect of Phoneutria nigriventer spider venom (PNV) on the gastric emptying of liquids was studied in 240 young adult Wistar rats (2-3 months of age) divided into subgroups of 8 animals each. The study was performed in 3 stages. Initially, PNV was injected into rats at doses of 0.19, 0.38 or 0.76 mg/kg and the effect on gastric emptying was assessed 30 min later. In the second stage, a time-course study was performed by injecting 0.76 mg PNV/kg and measuring the effect on gastric emptying 15, 60 and 120 min post-venom. In the last stage, in order to investigate the possible mechanisms of PNV influence on gastric emptying, one group of rats underwent subdiaphragmatic vagotomy and then received 0.76 mg PNV/kg while three other groups were pretreated iv with either prazosin (0.4 mg/kg), domperidone (1.0 mg/kg) or propranolol (0.6 mg/kg) and then given 0.38 or 0.76 mg PNV/kg. In this last stage, gastric retention was measured 30 min post-venom. Each animal received a saline test meal solution containing phenol red as a marker (60 microg/ml). Ten min after administering the test meal by gavage, gastric retention was determined by measuring the residual test meal marker concentration and the animals were sacrificed. PNV (0.76 mg/kg) provoked a significant delay in gastric emptying of liquids 15, 30 and 60 min after its administration. Propranolol partially interfered with gastric emptying in rats that had received 0.38 and 0.76 mg PNV/kg. Vagotomy and pretreatment of the rats with prazosin and domperidone had no effect. We conclude that the delay in the liquid gastric emptying observed in severely envenomed rats was probably due, at least in part, to a venom-stimulated release of catecholamines which inhibited gastric motility by activating smooth muscle beta-adrenergic receptors.