title: Contractile reaction of isolated frog aorta after X-irradiation.
abstract: The action of X-rays (50 kV, filtered by 0.3 mm Al) on helical strip of frog aorta (rana esculenta) has been investigated. The isolated preparations have a stable basal tone and are radio-sensitive to X-rays which induce reversible, dose-dependent, contractile responses. After repeated irradiation tachyphylaxis appears. The threshold doses are about 250 Rat 3 to 6 kR/min, antiadrenergic (phentolamine, propranolol), anticholinergic (atropin), antihistaminic (Neo-Bridal) and serotoninergic (Deseril) drugs have no visible influence on the X-ray induced reaction, i.e. these action mechanisms of the irradiation-induced contraction do not seem probable. Theophylline and cAMP inhibit the X-ray contraction probably non-specifically. Indometacin also inhibits the X-ray contraction: this suggests participation of prostaglandin-mechanism on the contraction of frog aorta after irradiation.
mesh_terms: D000818:Animals; D001011:Aorta / Q000528:radiation effects*; D001285:Atropine / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D008784:Methysergide / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000528:radiation effects*; D009130:Muscle, Smooth / Q000528:radiation effects; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011829:Radiation Dosage; D011893:Rana esculenta; D013806:Theophylline / Q000494:pharmacology
chemical_list: D001285:Atropine; D011433:Propranolol; D013806:Theophylline; D000242:Cyclic AMP; D007213:Indomethacin; D008784:Methysergide; D010646:Phentolamine