Abstract
Effect of six indole alkaloids and one synthetic compound on neuromuscular transmission was examined in the rat limb preparation in situ. Gardneramine inhibited the gastrocnemius contractions elicited by electrical stimulation of the sciatic nerve, but exerted little or no inhibition on the contractions elicited by direct stimulation of the muscle. The inhibitory effect of gardneramine was a little stronger than that of hexamethonium and was very weak when compared with that of d-tubocurarine. Gardnerine augmented both contractions elicited by nerve and muscle stimulation. Gardnutine, hydroxygardnutine, hirsutine, and one synthetic compound showed a long-lasting depressive effect on both contractions, while isorhynchophylline was little effective. These results indicate that only gardneramine affects neuromuscular transmission chiefly.
