Biomaterial Database

The mechanism of beta-bungarotoxin action. I. Modification of transmitter release at the neuromuscular junction. 1976

S G Oberg, and R B Kelly

The protein, beta-bungarotoxin, a presynaptic neurotoxin isolated from the venom of the snake Bungarus multicinctus, is known to inhibit mitochondrial function. Within 30 min after adding the toxin to a rat diaphragmphrenic nerve preparation, the quantal content increased tenfold and the frequency of miniature endplate potentials increased fourfold. No increase in miniature endplate potential frequency was seen in the absence of extracellular calcium. Since mitochondria may be involved in regulating intracellular calcium levels, the rate at which the transmitter release is turned off was studied by measuring delayed release in the presence and absence of toxin. Delayed release is elevated about eightfold by the toxin. If delayed release is due to residual calcium, as has been hypothesized, these data may be explained if the toxin does not alter the amount of calcium which enters the terminal, but rather the rate at which that calcium is removed. Alternatively, a calcium-dependent modification of the release process itself might be produced. The eventual reduction in transmitter output did not appear to result from depletion of the terminal of releaseable packets of transmitter, but does require extracellular calcium.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009469	Neuromuscular Junction	The synapse between a neuron and a muscle.	Myoneural Junction,Nerve-Muscle Preparation,Junction, Myoneural,Junction, Neuromuscular,Junctions, Myoneural,Junctions, Neuromuscular,Myoneural Junctions,Nerve Muscle Preparation,Nerve-Muscle Preparations,Neuromuscular Junctions,Preparation, Nerve-Muscle,Preparations, Nerve-Muscle
D002038	Bungarotoxins	Neurotoxic proteins from the venom of the banded or Formosan krait (Bungarus multicinctus, an elapid snake). alpha-Bungarotoxin blocks nicotinic acetylcholine receptors and has been used to isolate and study them; beta- and gamma-bungarotoxins act presynaptically causing acetylcholine release and depletion. Both alpha and beta forms have been characterized, the alpha being similar to the large, long or Type II neurotoxins from other elapid venoms.	alpha-Bungarotoxin,beta-Bungarotoxin,kappa-Bungarotoxin,alpha Bungarotoxin,beta Bungarotoxin,kappa Bungarotoxin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus