[The effect of alpha-adrenoreceptor stimulation and blockade on the myoelectrical activity of the small intestine and pyloric sphincter].

The administration of mesaton enhanced contractile activity of pyloric sphincter and diminished it in the duodenum in rabbits. The blockade of alpha-adrenoreceptors with dihydroergotoxin abolished the myoelectrical activity in the pyloric sphincter and sharply enhanced it in the duodenum. Both these effects could occur in the blockade and in the stimulation of alpha-adrenoreceptors of the ileum. The administration of mesaton against the background of the blockade of H-cholinoreceptors with bensohexonium never enhanced myoelectrical activity of the pyloric sphincter. The data obtained suggest different roles of alpha-adrenoreceptors in the pyloric sphincter, duodenum and ileum. The activating alpha-adrenoreceptors of the pyloric sphincter can be found on the neurons of the myenteric plexus.