Decomposition Products of Nucleoproteins and Related Substances and Muscle Sensitivity to Acetylcholine and Potassium. *

Abstract

Summary and Conclusions

1. The effect of decomposition products of nucleoproteins and related substances on the contraction of the rectus abdominis muscle induced by acetylcholine and potassium was studied. 2. Adenosine, adenine, adenylic acid, and uric acid did not modify the effect of acetylcholine. 3. Xanthine, methylxanthines, uracil, thiouracil, pyridine, 2-methyl-5-ethoxymethyl-6-amino pyrimidine, 4-methyl-5-β-hydroxyethyl thiazole, methylguanidine, and pyrol did not modify the effect of acetylcholine when used in low concentrations. They increased the effect of acetylcholine when present in higher concentrations. 4. Nucleic acid, alloxan, urea, thiourea, and piperidine decreased the effect of acetylcholine when used in higher concentrations. 5. Adenosine, adenine, guanine, xanthine, adenylic acid, uric acid, methylxanthines, uracil, thiouracil, pyridine, 2-methyl-5-ethoxymethyl-6-amino pyrimidine, 4-methy1-5-β-hydroxyethyl thiazole, thiourea, urea, methylguanidine, and pyrol increased the effect of potassium in inducing muscle contraction. 6. Nucleic acid, alloxan, and piperidme decreased the effect of potassium in inducing muscle contraction.