English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The weakness and fatigability of skeletal muscle in myasthenia gravis have been likened to similar phenomena which occur in curare poisoning. As the intensity of curarization increases, muscle groups weaken in a certain order. The same muscle groups are often affected in the same order as myasthenia gravis progresses. The mechanism of death by interference with respiration is often strikingly similar in the two conditions. These facts have suggested that myasthenia gravis may result from the presence in the body of a curarelike substance. In favor of this hypothesis could be cited (1) the great sensitivity of myasthenic patients toward curare (1), and (2) evidence for the production of this kind of substance by the muscles of myasthenic patients during exercise (2, 3). One of the effects of curare is to diminish or abolish the stimulating action of acetylcholine upon the neuromuscular endplate. In experimental animals, curarization produces simultaneously a decrease in the amplitude of the muscular twitch on stimulation of the motor nerve and a decrease in the twitch-like response to acetylcholine (4). If, as seems likely, this antagonism to acetylcholine is the factor responsible for the neuromuscular block of curare poisoning, then the phrase "curare-like" action implies the diminution or abolition of the stimulating effect of acetylcholine in skeletal muscle. If the hypothesis is correct that the weakness of myasthenia gravis is due to the presence of a curare-like substance, the myasthenic muscle should be less sensitive than normal to stimulation by acetylcholine. Two groups of investigators (5 to 8) have compared the effects of relatively large doses of intra-arterially injected acetylcholine upon skeletal muscle in normal and myasthenic man. Both drew the conclusion that myasthenic muscles are more sensitive to acetylcholine than normal muscles. The aim of the observations reported below was to check this conclusion by determining the response of normal and myasthenic muscles to threshold concentrations of acetylcholine. The previous conclusions could not be confirmed; myasthenic muscles were not notably more or less sensitive to acetylcholine than normal muscles.

SENSITIVITY OF SKELETAL MUSCLE TO INTRA-ARTERIAL ACETYLCHOLINE IN NORMAL AND MYASTHENIC MAN