Effects of black widow spider venom and latrocrustatoxin on crustacean nerve cells: Electrophysiological and ultrastructural study

Propiedades bioquímicas y fisiológicas del veneno del escorpión L. tredecimguttatus obenidor por estimulación eléctrica

“…Widow spider venom contains a complex mixture of components with different types of biological activities. When the crude homogenate from the black widow spider venom gland was applied to the junctions of the crustacean nerve-muscle preparation, it augmented and then suppressed both excitatory and inhibitory postsynaptic potentials, indicating that the venom has a presynaptic action at crustacean neuromuscular junction (5,18). Application of the homogenate to the neuromuscular junction of the frog caused an increase in the frequency of miniature end-plate potentials and a reduction in the number of synaptic vesicles in the nerve terminal (6,10).…”

α-Latrocrustatoxin Increases Neurotransmitter Release by Activating a Calcium Influx Pathway at Crayfish Neuromuscular Junction

“…Our data confirm and extend previous studies with this purified venom fraction (or with whole venom or a 65-kDa crustacean specific fraction). Thus it has been shown that both spontaneous and evoked transmitter release are initially enhanced at crustacean neuromuscular junctions treated with either BWSV or ␣-LCTX, followed by failure of transmission, at which point drastic morphological changes, including synaptic vesicle depletion and mitochondrial swelling, ensue (Burmistrov et al 1997;Fritz and Mauro 1982;Fritz et al 1980a,b;Kawai et al 1972). The minimally effective concentration used here was insufficient to lead to blockade of transmitter release or any obvious morphological derangement and revealed that the mechanism by which ␣-LCTX elicits Ca 2ϩ entry and enhancement of transmitter release is clearly dynamic (even though the rate of dissociation from the receptors is very slow), a phenomenon that may not be observed at higher, faster-acting toxin concentrations.…”

“…The venom of the black widow spider (Latrodectus mactans tredecimguttatus) contains a family of related neurotoxins, known as latrotoxins, which cause dramatic stimulation of exocytosis at synapses and from endocrine cells (Grishin 1998;Rosenthal and Meldolesi 1989). Latrotoxins have been de-scribed showing differential selectivity for vertebrate (Frontali et al 1976;Tzeng and Siekevitz 1978, but see also Umbach et al 1998), insect (Dulubova et al 1996;Grishin 1998;Krasnoperov et al 1992;Magazanik et al 1992), or crustacean synapses (Burmistrov et al 1997;Krasnoperov et al 1992), and these toxins share a similar domain structure (Grishin 1998;Kiyatkin et al 1990Kiyatkin et al , 1993. A fragment of the cDNA for ␣-latrocrustatoxin (␣-LCTX), a latrotoxin that is effective at crustacean synapses (Burmistrov et al 1997;Krasnoperov et al 1992), has been cloned and sequenced and showed 68 and 31% homology with the corresponding regions of ␣-latroinsectotoxin (␣-LIT) and ␣-latrotoxin (␣-LTX), respectively (Volynskii et al 1999).…”

“…Latrotoxins have been de-scribed showing differential selectivity for vertebrate (Frontali et al 1976;Tzeng and Siekevitz 1978, but see also Umbach et al 1998), insect (Dulubova et al 1996;Grishin 1998;Krasnoperov et al 1992;Magazanik et al 1992), or crustacean synapses (Burmistrov et al 1997;Krasnoperov et al 1992), and these toxins share a similar domain structure (Grishin 1998;Kiyatkin et al 1990Kiyatkin et al , 1993. A fragment of the cDNA for ␣-latrocrustatoxin (␣-LCTX), a latrotoxin that is effective at crustacean synapses (Burmistrov et al 1997;Krasnoperov et al 1992), has been cloned and sequenced and showed 68 and 31% homology with the corresponding regions of ␣-latroinsectotoxin (␣-LIT) and ␣-latrotoxin (␣-LTX), respectively (Volynskii et al 1999). The similarity of the latrotoxins in action and domain structure makes their taxonomic specificity all the more striking and emphasizes the need for detailed comparative studies of their actions before using them as tools for examining the molecular mechanisms controlling exocytosis.…”

“…Most of our understanding of the actions of latrotoxins comes from the work on ␣-LTX effects on vertebrate systems; the actions of latroinsectotoxins (LITXs) on insect synapses (Dulubova et al 1996;Magazanik et al 1992;Shatursky et al 1995) and ␣-LCTX on crustacean synapses (Burmistrov et al 1997) have been studied relatively little. ␣-LCTX has been shown to increase transmitter release from crustacean nerve terminals and earlier studies described the actions of either whole venom or a 65-kDa crustacean specific fraction (the relationship of which to the currently described 120-kDa ␣-LCTX is unknown) on either stretch receptor or neuromuscular junction preparations (Fritz and Mauro 1982;Fritz et al 1980a,b;Grasso and Paggi 1967;Kawai et al 1972), finding that these agents had profound electrophysiological and morphological consequences (including dramatic enhancement of transmitter release followed by block of transmission, synaptic vesicle depletion, and mitochondrial swelling).…”