In addition to local effects, scorpion envenomation produces systemic effects predominantly related to massive neurotransmitter release from central and peripheral nervous system. This neurotoxic activity has been attributed to venom-containing peptides that have great specificity and affinity to ion channels, resulting in activation, inactivation, blockade or alterations of its opening/closing mechanisms. Scorpion neurotoxins have been widely used as pharmacological tools to understand the ion channel structure and its physiology, as well as to evaluate its contribution to many diseases such as channelopathy, epilepsy, facial paralysis, muscular diseases, cardiac arrhythmia and pain syndromes, thus offering novel strategies for developing therapeutic drugs. Tityus bahiensis is the major responsible for scorpion stings on São Paulo State (and second more important in Brazil); however, its total venom and isolated fractions remain scarcely studied, especially regarding to the peripheral nervous system and ion channel activation. The aim of this work is to evaluate the activities of T. bahiensis venom and its isolated fractions on (i) different isolated nerve/skeletal muscle preparations under direct and indirect/field stimulations (somatic activity); (ii) rat vas deferens preparation upon to electrical-field stimulation (autonomic activity); (iii) electrophysiological experiments to analyze the resting membrane potential (skeletal and smooth muscle), end-plate potentials (spontaneous and evoked currents), nerve action potential, and perineural waveforms (calcium, sodium and potassium currents); and (iv) evaluation of the individual potassium, sodium and calcium channel currents using voltage-clamp and patch-clamp techniques. The proposed project will afford knowledge of the pre and postsynaptic effects caused by T. bahiensis venom neurotoxins. The results of this work could encourage the study/isolation of molecules with pharmacological potential that may be used as research tools.
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