[The contractile reactions of aortic segments to noradrenaline in the immediate and late postradiation periods].

It is shown on isolated aorta preparations, that external gamma-irradiation of rats in dose 6 Gy results in intensification of endothelium-dependent relaxation which reaches of maximum in 30th days of post-radiation period. Constriction effect of norepinephrine on preparations without endothelium in remote terms after irradiation decreases with maximum on 90th days.