Contribution to the study of vitamin B1. XXIV. Action of acetylaneurine on the isolated duodenum of a rabbit

Rodrigues, C. rdoso, M.

Duodenal segments of rabbits were placed in a Tyrode solution (pH 7.4-7.7) maintained at 38[degree]C, and acetylaneurine added at the rate of 5-25 mg/100 ml Tyrode solution. In addition, in some experiments acetylcholine was added, either before or after addition of acetylaneurine, in amounts of 10-5 g. In nearly all cases, the latter substance gave rise to an increase in the tonus and to a rise in the amplitude of the contractions. It partly or completely inhibited the effects of acetylcholine, when the latter was added last. When acetylcholine was added first, the duodenum contracted, and acetylaneurine addition resulted nearly always in a decline in the tonus. The action of this substance is opposite to that of co-carboxylase, and similar to but more potent than the action of aneurine.