RÉSUMÉ
The cardiovascular and antiarrhythmic effects of purified extract of the inner bark of Anacardium Occidentale (cashew tree) have been documented. The antiarrhythmic effect was shown to be due to myoinositol of which the bark contains 25 percent w/w. With the exception of succinylcholine chloride, both d-tubocurarine chloride and pancuronium bromide are potent non-depolarising neuromuscular blocking agents. It is an accepted fact that there is no satisfactory antagonist for the depolarising blocking drugs such as succinycholine chloride. It was interesting to note that anacardium occidentale (AO) blocked the action of all 3 drugs on the rat phrenic-nerve-diaphragm neuromuscular preparation. A total dose of 1mg in a 50ml organ bath blocks the action of 100ug of d-tubocurarine 200ug of succinylcholine chloride and 200ug of pancuronium bromide. Pancuronium bromide is about 5 times as potent as d-tubocurarine chloride. These results indicate that AO is more effective against pancuronium. A graphical representation of the result showed that the antagonism against these 3 drugs is competitive. The onset of action of AO is slow and each dose was allowed to act for 5 minutes before the additioin of the agonist. The non-depolarising drugs are antagonised by acetylcholine and the anti-cholinesterases, but preliminary experiments showed that AO had no acetylcholine nor anticholinesterase properties. The findings indicate that there may be some other mechanism of action of non-depolarising blocking drugs than occupation of the nicotinic receptors on the motor and plate (AU)