Use of Parasympathetic Stimulation in the Production of Bloody Diarrhea in Dogs, with Reference to the Role of Red Cell and Colon Cholinesterase

Abstract

Summary 1.Postganglionic celiac, superior and inferior mesenteric sympathectomy was associated with chronic, nonbloody diarrhea in 10 dogs. 2.Daily intramuscular injections of Mecholyl in oil (0.5 to 4.0 mg. per kg. per day) in 8 dogs led to bloody diarrhea in 3. In 2 of these the dose was 2.5 to 4.0 mg. per kg.; in the third, 1.0 mg. per kg. was given. 3.In contrast, acute and massive bloody diarrhea was produced in 4 out of 5 of these animals by administration of 0.5 to 1.5 mg. per kg. of Mecholyl following reduction of red blood cell and colon cholinesterase to 26 per cent and 30 per cent or less of control values, respectively, by means of oral administration of 1.0 mg. per kg. of octamethylpyrophosphoramide (OMPA) over a period of many weeks. Of importance, OMPA per se did not lead to bleeding, except in 1 animal which received 4 mg. per kg. for five days. 4.Explanation for this effect may lie in the results of several colon motility experiments which demonstrated that inhibition of colon tissue cholinesterase (Che potentiates contractile effect of a parasympathomimetic agent, although threshold dosage remains unaltered. 5.The significance of these findings is discussed in the light of the role of autonomic influences upon the colon in human beings, with reference to idiopathic ulcerative colitis.