Increase of permeability of synaptosomes and liposomes by the heavy chain of tetanus toxin.

In search of a role for the heavy chain of tetanus toxin in poisoning, its actions on natural and artificial membranes have been assessed. The heavy chain increases the permeability of synaptosomes to lactate dehydrogenase and potassium ions, and promotes the outward shift of the lipophilic cation tetraphenylphosphonium which is a particularly sensitive indicator for depolarization. Independent of the assay system the potency of the heavy chain is high, i.

Cooperative action of the light chain of tetanus toxin and the heavy chain of botulinum toxin type A on the transmitter release of mammalian motor endplates.

Purified heavy chain of botulinum toxin type A and light chain of tetanus toxin were combined to form a chimeric toxin. It was active on the mouse phrenic nerve-hemidiaphragm with a potency 6 times higher than that of native tetanus toxin. Electrophysiological data from poisoned neuromuscular junctions revealed that the pattern of nerve-evoked and spontaneous transmitter release was equivalent to that seen with tetanus toxin i.

Chains and fragments of tetanus toxin, and their contribution to toxicity.

1. Single-chain toxin is enzymatically converted into two-chain isotoxins which differ from the precursor by their higher pharmacological activity, acidity and hydrophilicity. The interchain disulfide bridge and the disulfide loop within fragment C have been located at the amino acid level.

Chains and fragments of tetanus toxin. Separation, reassociation and pharmacological properties.

Tetanus toxin, as obtained from bacterial culture filtrates, consists of two chains. Since their roles in poisoning are unknown, we have made a detailed study of their preparation, reassociation and pharmacological activity. 1.

The tetanus toxin light chain inhibits exocytosis.

The intracellular action on exocytosis of various forms of tetanus toxin was studied using adrenal medullary chromaffin cells, the membrane barrier of which has been removed by permeabilization with streptolysin O. Such cells still release catecholamines on stimulation with calcium. The two-chain form of tetanus toxin (67 nmol/l) strongly inhibited exocytosis, but only if dithiothreitol was present as a reducing agent.

Palytoxin promotes potassium outflow from erythrocytes, HeLa and bovine adrenomedullary cells through its interaction with Na+, K+ -ATPase.

Erythrocytes from four mammalian species were compared with regard to K+ loss triggered by palytoxin, to Na+, K+ -ATPase activity, and to ouabain sensitivity of both events. Palytoxin sensitivity (EC50) decreased in the order rat, man (approximately equal to 1 pM) greater than cattle (approximately equal to 500 pM) greater than dog (greater than 10 nM). Na+, K+ -ATPase activity, as measured by Rb uptake, was in the series rat greater than man greater than cattle greater than dog.