Potentiation of the response to histamine by picolylamines

The response of the isolated ileum of the guinea-pig to histamine is potentiated in the presence of 2-, 3- or 4-picolylamine. These compounds have been found to inhibit the histaminase and/or "diamine oxidase" of pig kidney. The three corresponding picolylmethylamines did not potentiate the response of the ileum to histamine; they were without significant affinity for the pig kidney oxidase. It is suggested that the potentiating action of the three primary amines is due to their inhibitory action on histaminase. The responses of the ileum to acetylcholine and 5-hydroxytryptamine were not potentiated.