Pregnancy

Vascular Hyper-Responsiveness to Adrenomedullin During Pregnancy Is Associated with Increased Generation of Cyclic Nucleotides in Rat Mesenteric Artery

Abstract
Cardiovascular adaptation is a hallmark of pregnancy. Here, we report vascular hyperresponsiveness to an endogenous vasodilator, adrenomedullin (ADM), during pregnancy. Intravenous administration of ADM dose-dependently decreased the mean arterial pressure and the decrease was significantly greater in pregnant compared to non-pregnant rats without affecting the heart rate. In endothelium-intact mesenteric artery precontracted by ED70 concentration of norepinephrine, the potency and efficacy of ADM in causing the vasodilation mesenteric arterial rings from pregnant rats are significantly higher compared to non-pregnant females at diestrus. The magnitude of inhibition of concentration-dependent-response to ADM by the inhibition of either soluble guanylate cyclase or adenylate cyclase was greater in pregnant rats. Moreover, the ADM-induced cyclic nucleotide generation, both cGMP and cAMP, in mesenteric artery are elevated during pregnancy and sensitive to the receptor antagonist, ADM22-52. These findings suggest that during pregnancy, the vasodilatory effects of ADM are greater and are associated with increased generation of cyclic nucleotides in resistance vessels, and these changes may be part of the cardiovascular adaptations that occur during pregnancy.

Key words: Pregnancy • Cyclic adenosine monophosphate • Cyclic guanosine monophosphate

This article has been cited by other articles:

				H.W.F. van Eijndhoven, R. Aardenburg, M.E.A. Spaanderman, J.G.R. De Mey, and L.L.H. Peeters Pregnancy Enhances the Prejunctional Vasodilator Response to Adrenomedullin in Selective Regions of the Arterial Bed of Wistar Rats Reproductive Sciences, December 1, 2007; 14(8): 771 - 779. [Abstract] [PDF]