Paralytic properties of 4-N, N-dimethylamino-1,2-dithiolane (nereistoxin).

Canine peroneal-tibialis anterior nerve-muscle preparations have been used as a model system to investigate the neuromuscular blocking action of nereistoxin (NT). Intravenous administration of 1 mg/kg of NT results in 50% neuromuscular blockade within 2 to 5 min. In the absence of corrective intervention this quantity of NT will cause respiratory paralysis and death within a few minutes. Following the intravenous administration of NT there occurs an immediate and transient rise in heart and fall in systolic and diastolic blood pressure; however, respiratory paralysis rather than cardiovascular failure is the cause of death when no corrective measures are employed. Neostigmine, 5-hydroxytryptamine, acetylcholine and potassium ions antagonize NT paralysis. Neostigmine, however, appears to be the most effective in producing an antiblocking action of sufficient magnitude and duration of action to be of value as an antidote in NT poisoning. Potentiation of contractions was evident in the partially paralyzed preparation following a brief period of indirect tetanic stimulation.