RESUMO
Antivenom in order to be effective in the treatment of coral snake accidents must be injected very soon after the bite owing to the rapid rate of absorption of the venom neurotoxins. As this is not always possible, other forms of treatment besides serotherapy must be employed to avoid asphyxia and death. Neostigmine and artificial respiration are used for this purpose. Neostigmine restores neuromuscular transmission if the venom-induced blockade results from a reversible interaction of its neurotoxins with the end-plate receptors. This is the mechanism of the neuromuscular blockade produced by the venom of M. frontalis snakes from centereastern and southern Brazil, and Argentine. Neostigmine is able, therefore, to antagonize the blockade, and has been shown to be very effective in the treatment of the experimental envenomation of dogs and monkeys. In the present communication, two cases of M. frontalis accidents treated with antivenom and neostigmine are reported. In both, neostigmine was successful in producing regression of the paralysis, confirming the effectiveness shown in the treatment of the poisoning induced in animals by M. frontalis venom.
Assuntos
Inibidores da Colinesterase/farmacologia , Elapidae , Neostigmina/uso terapêutico , Mordeduras de Serpentes/terapia , Adulto , Animais , Antivenenos/farmacologia , Antivenenos/uso terapêutico , Inibidores da Colinesterase/uso terapêutico , Cães , Venenos Elapídicos/farmacologia , Venenos Elapídicos/toxicidade , Humanos , Masculino , Neostigmina/farmacologia , Neostigmina/toxicidade , Respiração Artificial , Resultado do TratamentoRESUMO
Ketamine is an anaesthetic interacting with several neurotransmitters. Among others, ketamine exerts some cholinergic actions (ACh). This paper presents the results of studying the interaction of ketamine with ACh in two animal species. Atropine slightly increased the time of immobility produced by ketamine injections in rats. Meanwhile, neostigmine slightly decreased such immobility. Ketamine resulted similar in behavioral actions and shared some electroencephalographic (EEG) actions of scopolamine in cats. The most striking interaction consisted on an antagonism of ketamine on the action of anticholinesterase agents. In both species, ketamine blocked the EEG and the behavioral toxic effects of neostigmine and physostigmine. Notwithstanding, the anticholinesterase agents were unable in reducing the actions of ketamine. This partial cholinergic agonist action of ketamine support certain but limited use of the anesthetic against insecticidal anticholinesterase poisoning.