Effects of Phoneutria Nigriventer Spider Venom on Mouse Peripheral Nerve

Abstract

SUMMARYA physiological and morphological study has been made ofthe effects of the venom of the spider Phoneutria nigriventer on peripheral nerve and skeletal muscle of the mouse. Venom was injected either into the sciatic nerve, via a glass micropipette, or into the calf muscles. Repetitive firing of nerve fibres commenced within seconds ofinjection and caused fasciculation ofmuscles and irregular trains of end-plate potentials. These physiological disturbances were associated with swelling of the nodal and paranodal axoplasm and the development of vacuoles in the periaxonal space. The segments of internode between the vacuoles became attenuated, with an increase in the density of axoplasmic organelles and a reduction in axonal calibre. The repetitive firing ceased after 1-3 h with development of conduction block. Both the physiological and the morphological abnormalities gradually resolved and by 24 h nerve conduction and morphology had largely returned to normal. It seems likely that these short-lived abnormalities are a consequence of the influx of sodium ions at the nodes of Ranvier, caused by the action of the venom on sodium channels.

MORPHOLOGICAL ABNORMALITIES IN MYELINATED NERVE FIBRES CAUSED BY LEIURUS, CENTRUROIDES AND PHONEUTRIA VENOMS AND THEIR PREVENTION BY TETRODOTOXIN

“…The scorpion venoms caused morphological alterations that closely resembled those produced by Phoneutria venom and described in detail by Cruz-Hofling, Love, Brook & Duchen (1985). Within 15-30 min most myelinated fibres were abnormal.…”

Blockade of acetylcholine release at the motor endplate by a polypeptide from the venom of Phoneutria nigriventer

“…These effects were attributed to activation of voltage-dependent sodium channels in both nerve and muscle fibres (Fontana & Vital-Brasil, 1985). Morphological changes produced by the venom in peripheral nerves of mice were also reported (Cruz-Hofling et al, 1985;Love et al, 1986).…”

Natural history ofPhoneutria boliviensis(Araneae: Ctenidae): habitats, reproductive behavior, postembryonic development and prey-wrapping

“…They are considered aggressive, and among the most medically important spiders in the world (Foelix 2010). Their venom has a neurotoxic action (Foelix 2010) and many researchers have analyzed its components and the epidemiology of bites (Bü cherl 1953a(Bü cherl , b, 1956Cruz-Hö fling et al 1985;Marangoni et al 1993;Pineda & Florez 2002;Florez et al 2003;Garcia et al 2008;Maguiñ a et al 2008).…”