Histamine stimulation of canine colonic epithelium: Potentiation by hydroxylamines

Hydroxylamine derivatives markedly potentiated responses of the canine colonic mucosa to histamine, but not to carbachol or 5HT. Effects noted were produced upon either luminal or serosal addition of the agents, suggesting an intracellular mechanism. Similar potentiations were observed with a phosphodiesterase inhibitor, IBMX, suggesting that hydroxylamines could act by altering cyclic nucleotide levels. Since such derivatives could be produced as intermediates by colonic bacteria, the effects noted could have pathological implications.