Cassian Bon

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The effects of alpha-bungarotoxin from Bungarus multicinctus and Bungarus caeruleus were studied on three types of cholinergic response in Aplysia central neurones. These responses are the result of three distinct changes in ionic permeability: selective increases in permeabiliyt to Na, Cl and K, respectively. It was shown that 10(-5) M alpha-bungarotoxin(More)
Crotoxin is a potent neurotoxin from the venom of Crotalus durissus terrificus. It is composed of two subunits: a basic phospholipase A2 with low toxicity (component B) and an acidic protein seemingly devoid of intrinsic biological activity (component A). Crotoxin and its isolated phospholipase subunit block the depolarisation caused by cholinergic agonists(More)
Crotoxin is a phospholipase A2 neurotoxin that impairs the release of acetylcholine at neuromuscular junctions, primarily at the presynaptic level. It associates a phospholipase A2 subunit, CB, with a chaperon subunit, CA. We have shown elsewhere that the purely cholinergic synaptosomes from the Torpedo electric organ provided a convenient model to study(More)
Crotoxin is a potent presynaptic neurotoxin from the venom of the rattlesnake Crotalus durissus terrificus. It is composed of the noncovalent and synergistic association of a weakly toxic phospholipase A2, CB, and a nontoxic three-chain subunit, CA, which increases the lethal potency of CB. The A-56.36 mAb is able to dissociate the crotoxin complex by(More)
The mechanisms by which antivenom neutralizes the venom are still poorly understood. In the present work, we studied the effects of antivenom, constituted with either F(ab')2 or Fab, on the processes of absorption and elimination of Vipera aspis venom in experimentally envenomed rabbits. We first concluded from this study that during the few hours after(More)
alpha-Latrotoxin, a high molecular weight protein (130,000) purified from the venom of the black widow spider, and a partially purified neurotoxin, glycerotoxin, prepared from extracts of the jaw glands of the polichaete annelid Glycera convoluta, were previously found to induce similar effects (stimulation of quantal acetylcholine release) at the frog(More)
The crude extract of glands appended to the jaws of the polychaete annelid Glycera convoluta induces an important increase in the spontaneous quantal transmitter release on frog and crayfish neuromuscular junctions and on Torpedo nerve-electroplaque junctions. The venom similarly triggers acetylcholine (ACh) release from synaptosomes purified from Torpedo(More)
We adapted a method, originally described by Israel et al. (1976) for the preparation of cholinergic nerve endings from Torpedo, to deal with a larger quantity of electric tissue. We followed the distribution of acetylcholine (ACh), ATP, acetylcholine receptor (AChR), choline acetyltransferase (ChAT), ouabain-resistant and -sensitive ATPase, lactate(More)
p-(Dimethylamino)benzenediazonium fluoroborate (DDF) behaves, in the dark, as a reversible competitive antagonist of the electrical response of Electrophorus electricus electroplaque to acetylcholine and of the acetylcholine-gated single-channel currents recorded in the C2 mouse cell line. This chemically stable but highly photoreactive compound binds(More)
Ceruleotoxin, a toxin component of Bungarus caeuleus venom, blocks in vivo the depolarisation caused by carbamylcholine on the isolated electroplaque from Electrophorus electricus and in vitro in increase of 22Na+ and 42K+ efflux caused by cholinergie agonists on excitable receptor-rich microsacs prepared from Torpedo marmorata electric organ. However, at(More)