title: Effect of ionizing irradiation on the physiological activity of cyclic adenosine monophosphate on smooth muscle preparations.
abstract: The effect of ionizing irradiation on the physiological activity of cyclic adenosine monophosphate (cAMP) in smooth muscle preparations from frog lung was studied. cAMP, given as dibutyryl salt (dib-cAMP) inhibited the radiation induced contractions of the muscle in a manner similar to the action of theophylline. In vitro irradiation of dib-cAMP resulted in an alteration of the chemical structure of this substance, i.e., formation of monobutyryl-cAMP and further derivatives as well as a decomposition of the purine structure. There was also a loss of the relaxing activity of irradiated cAMP on the muscle tone of frog lung preparations. The physiologically measured inactivation of dib-cAMP was far more pronounced than the chemical alteration. An inhibitory effect of the reaction products is postulated.
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology / Q000528:radiation effects*; D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes; D000242:Cyclic AMP / Q000502:physiology*; D008168:Lung / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D011898:Ranidae
chemical_list: D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes; D003994:Bucladesine; D000242:Cyclic AMP