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Cardiovascular effects of felypressin (FEL) were studied in Wistar rats. Heart rate and mean arterial pressure measurements were taken in awake rats treated with vasopressin (AVP), FEL, or epinephrine (EPI). Each group received either an intravenous (IV) or an intracerebroventricular V1 receptor antagonist, saline, area postrema removal, or sham surgery. Analysis of variance and Student-Newman-Keuls (P < .05) were applied. Felypressin and AVP induced a pressor effect, and bradycardia was inhibited by IV V1 antagonist. Intracerebroventricular V1 antagonist and area postrema removal enhanced their pressor effects. Epinephrine induced a higher pressor effect and a similar bradycardia that was not affected by the treatments. It was concluded that FEL depends on V1 receptors to induce pressor and bradycardic effects, and that it produces a high relationship between bradycardia and mean arterial pressure variation depending on area postrema and central V1 receptors. These effects are potentially less harmful to the cardiovascular system than the effects of EPI.Abstract
Mean and SEM of mean arterial pressure of the rats submitted to intravenous (IV) injection of 240 ng kg−1 of felypressin (FEL), 250 ng kg−1 of vasopressin (AVP), or 2 μg kg−1 of epinephrine (EPI) after IV injection of 0.9% NaCl, IV injection of 15 μg kg−1 of β-mercapto-β,β-cyclopentamethylenepropionyl-0 methyl-tyrosine, arginine vasopressin (β-MER), intracerebroventricular (ICV) injection of 100 ng of B-mer, or removal (APX) or sham removal (APS) of area postrema. Different letters mean a statistical difference (P < .05) between different treatments of the same group. * P < .05 versus EPI group.
Mean and SEM of heart rate of the rats submitted to intravenous (IV) injection of 240 ng kg−1 of felypressin (FEL), 250 ng kg−1 of vasopressin (AVP), or 2 μg kg−1 of epinephrine (EPI) after IV injection of 0.9% NaCl, IV injection of 15 μg kg−1 of β-mercapto-β,β-cyclopentamethylenepropionyl-0 methyl-tyrosine, arginine vasopressin (β-MER), intracerebroventricular (ICV) injection of 100 ng of B-MER, or removal (APX) or sham removal (APS) of area postrema. Different letters mean a statistical difference (P < .05) between different treatments of the same group.
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