Increased receptor expression supports vascular reactivity of the rabbit aorta during preservation

Up to 48 h of preservation, the adrenergic pathway and its receptors support vasoconstriction and vasodilation, despite a significant deterioration in the prostanoid pathway.

Aortic rings preserved in Krebs-Henseleit solution were evaluated fresh (t0), 24 h (t24) and 48 h (t48) after harvest for (i) vascular reactivity as sensitivity (pD2) and maximum effect in response to potassium chloride, U46619 (thromboxane-A2 agonist), phenylephrine, carbachol and isoproterenol, in an organ bath; and for (ii) expression of α1, β2 and thromboxane-prostanoid receptors, by immunofluorescence.

Compared to the control, after 24 h of preservation, potassium chloride-induced pD2 increased a significant 3.6%, whereas U46619-induced vasoconstriction decreased 9%. None of the agonists affected vasodilation. Intimal and medial α1 receptor expression increased 2.5-fold. After 48 h of preservation, α1 expression and vasoconstrictor responses remained similar to those after 24 h of preservation, but in vasodilation the carbachol-induced maximum effect decreased 30% whereas isoproterenol-induced pD2 increased 4% and the maximum effect increased 10%. TP and β2 expression in the intima and media increased 1.8- and 2.5-fold, respectively. Conclusions: Up to 48 h of preservation, the adrenergic pathway and its receptors support vasoconstriction and vasodilation, despite a significant deterioration in the prostanoid pathway.