Biphasic effects of single-dose intravenous injection of uridine adenosine tetraphosphate on blood pressure in mice.

Purpose: To explore the effects of a single dose of uridine adenosine tetraphosphate (UpA) administered through the tail vein, on the blood pressure of mice.

Methods: The mice were separated into three groups: the UpA group, the norepinephrine (NA) group, and the α, β-methylene adenosine triphosphate (α, β-meATP) group. Each group of mice were injected drugs through the tail vein at 1, 3, 10, and 30 nmol/kg doses in an ascending order. Additionally, six mice were injected UpA through the tail vein at 20, 40, 60, and 80 nmol/kg doses in an ascending order. The administration intervals for each dose were 20 min.

Results: Mice in these groups experienced a rapid increase in blood pressure, reaching its peak within 10 s after drug administration. It took approximately 120 s for the blood pressure to return to baseline levels after the administration of the drugs in both the NA and α, β-meATP groups. After higher doses of UpA were administered to the mice, their blood pressure exhibited biphasic changes. Initially, blood pressure of the mice rapidly dropped to a minimum within 10 s, then rose rapidly to a peak within 30 s. Subsequently, it gradually declined, taking around 10 min to return to the levels before the drug administration.

Conclusion: Compared to NA and α, β-meATP, UpA, which contains purine and pyrimidine components, displayed a weaker blood pressure-elevating potency. Through its corresponding structure, UpA exerted vasodilatory and vasoconstrictive effects throughout the entire experiment resulting in biphasic changes in blood pressure.