Effect of Prolonged Cold Storage on the Contractile Response of Strips of Rabbit Aorta to Various Agents

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Abstract
After 2 days in cold storage (2.0 ± 0.5°C), the contractile response of spiral strips of rabbit aorta to low concentrations (10-9 to 10-10) of epinephrine and of norepinephrine was potentiated; after storage for 4 to 7 days, an increased contractile response to high concentrations (10-8 to 10-6M) of these catecholamines was also observed. Reserpine-pretreated strips showed potentiation of epinephrine- and norepinephrine-induced contractions, but only after 2 to 7 days in cold storage. Another result of several days of cold storage was a decrease or loss of contractile response to nicotine (10-5 to 10-6M), tyramine (10-4 to 10-6M), and potassium (10 to 40 mM). Potentiation of the contractile response to epinephrine and to norepinephrine was also observed in potassium depolarized strips at low temperature (19°C). After incubation of the depolarized or cold-stored strips in the Ca-free medium, no potentiation of epinephrine- or norepinephrine-induced contractions was observed. These results indicate that cold storage, up to 7 days, does not interfere with the activation system related to epinephrine- or norepinephrine-induced contractions. However, such treatment does affect the membrane system involved in potassium-induced contraction. The decreased response to nicotine and tyramine after several days of cold storage may be due to the unavailability of tissue catecholamine. No significant histopathologic changes were observed in any layer of the aorta after cold storage up to 7 days.