Induction of localized differences in rat uterine radial artery behavior and structure during gestation

Local Versus Systemic Influences on Uterine Vascular Reactivity During Pregnancy in the Single-Horn Gravid Rat

“…As the results indicate, sensitivity to acetylcholine was similar in vessels from both horns, with values that were comparable to those previously reported in pregnant animals. 9 Because the arterial diameter response integrates both endothelial and vascular smooth muscle influences (ie, reflects both the amount of a vasodilator released by the endothelium and the sensitivity of vascular smooth muscle to its effect), and in view of the aforementioned differences in nitrodilator sensitivity, it is difficult to attribute the effect to either cell type alone. The pattern of increased basal endothelial calcium in vessels from the pregnant horn is consistent with that measured earlier in uterine vessels from pregnant versus nonpregnant animals, 9 indicating that local rather than systemic factors play the predominant role in determining this parameter.…”

“…9 The application of ACh increased endothelial cell [Ca 2þ ] i in a concentration-dependent manner, although there were no significant differences detected between horns in either the initial transient ( Figure 5A) or sustained ( Figure 5B) responses.…”

“…[6][7][8] Many investigators have interrogated the uterine vasculature to understand how its reactivity is altered during pregnancy, and the picture that emerges is complex. Experiments have demonstrated that the smooth muscle in uterine arteries is more sensitive to adrenergic stimulation and less sensitive to nitrate signaling (eg, sodium nitroprusside, SNP); [9][10][11] conversely, endothelial cell-mediated vasodilatation is generally augmented in pregnant animals, most likely due to an upregulation of receptors, intracellular calcium signaling pathways, and vasodilator release. 12 The purpose of this study was to elucidate the role of local versus systemic factors on changes in uterine vascular reactivity during pregnancy.…”

Impact of Experimental Diabetes on the Maternal Uterine Vascular Remodeling During Rat Pregnancy

“…Therefore, the proximal unmodified portion of the uteroplacental radial arteries becomes the main site of vascular resistance in the uteroplacental circulation of humans and animals with a hemochorial placentation. 6,15,16,19 Arterial compliance and distensibility of the uterine vasculature are also affected by pregnancy. In the MUA of sheep, higher stress-strain ratios were found in late pregnant compared to nonpregnant animals, suggesting an increased arterial stiffness and decreased arterial compliance.…”

“…5,8,9 This phenomenon has been shown in both the main uterine artery (MUA) as well as in the smaller uterine resistance arteries in multiple species including sheep, pigs, rats, and humans. 7,8,[10][11][12][13][14][15] The uterine spiral arteries-the distal extensions of uteroplacental radial arteries supplying the placenta-further undergo trophoblast-induced remodeling, with trophoblast invasion into the vascular wall and widening of the vascular lumen. 6,[16][17][18] The spiral arteries become progressively larger and more tortuous with replacement of the normal musculoelastic wall with fibrous tissue and loss of their constrictor function.…”