Blood flow during pregnancy in the rat: I. Flow patterns to maternal organs

Buelke-Sam, J.; Nelson, C. J.; Byrd, Richard A.; Holson, Joseph F.

doi:10.1002/tera.1420260309

Cited by 44 publications

(20 citation statements)

References 35 publications

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“…The blood flow per placenta of the N fetuses, 0.50-0.95 ml/rnin, was in the range of previously reported flow rates of rats in late gestation (2,3,5,IS,16,21,29,34). Also, our values of renal blood flow and pulmonary blood flow are in agreement with those found in previous investigations (20,31).…”

Section: Resultssupporting

confidence: 92%

Diabetes in Pregnancy: Decreased Placental Blood Flow and Disturbed Fetal Development in the Rat

Eriksson

Jansson

1984

Pediatr Res

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November 29, 1983. Vol. 18, No.8, 1984 Printed in U.S.A. Diabetes in Pregnancy: Decreased Placental Blood Flow and Disturbed Fetal Development in the Rat ULF J. ERIKSSON(3' ) AND LEIF JANSSON Department ofMedical Cell Biology, University ofUppsala, Uppsala, S weden SummaryPlacental blood flow was measured with the aid of radioactive microspheres, in normal (N) and manifest diabetic (MD) rats, and related to fetal body growth and incidence of congenital malformations. The total blood flow in the placentae of the MD rats was decreased to about one-half of the normal flow on gestational days 20 and 22..The placentae of the MD offspring were enlarged, whereas the fetuses in this group were smaller than normal. Thus , the placental blood flow per placental weight was drastically decreased in the MD fetuses on both days 20 and 22. In contrast, the placental blood flow per fetal weight was not different in the N and MD groups on gestational day 20 whereas it was decreased in the MD offspring on gestational day 22. Placental blood flow in the malformed fetuses. of the MD group . did not differ significantly from that in the nonmalformed MD fetuses.Abbreviations N, normal control rat (nondiabetic) N20 or N22, normal pregnant rat on gestational day 20 or 22 MD, manifest diabetic rat (serum glucose level exceeding 20 mmol/liter) MD20 or MD22, pregnant manifest diabetic rat on gestational day 20 or 22

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Section: Resultssupporting

confidence: 92%

Diabetes in Pregnancy: Decreased Placental Blood Flow and Disturbed Fetal Development in the Rat

Eriksson

Jansson

1984

Pediatr Res

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“…In contrast, a study using MR reported an ϳ20% decrease in CBF during pregnancy; however, this was compared with postpartum and not prepregnancy values (83). Studies have used microspheres to measure absolute CBF in late-pregnant rats and found a nonsignificant 5-10% increase in CBF compared with the nonpregnant state (15,26). Overall, although studies reporting the effect of pregnancy on CBF in women are contradictory, the use of animals that allowed invasive measurements suggests CBF remains similar in pregnancy to the nonpregnant state.…”

Section: Cbf Autoregulation and Hemodynamicsmentioning

confidence: 93%

“…Overall, the extension of autoregulation to higher and lower pressures may be protective of the brain, especially during parturition. There is no significant change in basal cerebral blood flow in the pregnant compared with the nonpregnant state, which is only ϳ10% increased globally (15,26). (17, 26).…”

Section: Function and Structure Of The Cerebrovasculaturementioning

confidence: 99%

The Cerebral Circulation During Pregnancy: Adapting to Preserve Normalcy

Johnson

Cipolla

2015

Physiology

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The adaptation of the brain and cerebral circulation to pregnancy are unique compared with other organs and circulatory systems, ultimately functioning to maintain brain homeostasis. In this review, the effect of pregnancy on critical functions of the cerebral circulation is discussed, including changes occurring at the endothelium and blood-brain barrier, and changes in the structure and function of cerebral arteries and arterioles, hemodynamics, and cerebral blood flow autoregulation. The brain is an organ of high metabolic demand that consumes ϳ20% of the body's oxygen at rest, despite comprising only 2% of body weight (77). Importantly, the brain has a relatively narrow capacity to tolerate changes in ion and water balance, and blood flow (77). The brain is also unique in that it is enclosed in a rigid skull, and therefore increased vascular permeability or volume could result in detrimentally increased intracranial pressure that can cause serious neurological symptoms, brain herniation, and even death. Thus there is a need to maintain tight control of cerebral blood flow (CBF) and water flux in the face of a 40 -50% increase in plasma volume and cardiac output during pregnancy and a decline in systemic vascular resistance necessary for the maintenance of a healthy blood pressure (28). In contrast to other organs outside the central nervous system that undergo substantial increases in both perfusion and transvascular filtration during pregnancy, including the uterus, kidney, and heart, the cerebral circulation must resist these adaptations to counterbalance global hemodynamic changes to maintain the delicate microenvironment of the brain. Thus the adaptation of the brain and cerebral circulation to pregnancy appears to be to maintain normalcy despite substantial hormonal and cardiovascular changes in almost every other organ. Throughout this review, the effect of pregnancy on several aspects of the cerebral circulation will be discussed, including the cerebral endothelium and blood-brain barrier (BBB), the structure and function of the cerebrovasculature, hemodynamics, and CBF autoregulation. Furthermore, in the context of these cerebrovascular adaptations, the risk for neurological complications that arises in women with preeclampsia, a dangerous hypertensive complication of pregnancy, will be considered. Preeclampsia affects 3-8% of all pregnancies and is defined as the appearance of hypertension and proteinuria after week 20 of gestation. Many organs are affected by preeclampsia, including the brain, putting women at risk of seizure and hemorrhage. In fact, the cerebral circulation has a central role in neurological complications of preeclampsia, and thus understanding how pregnancy and preeclampsia affect the cerebrovasculature is of interest. Vasomotor Responses to Circulating FactorsOne of the most important adaptations of the cerebral circulation during pregnancy is to counteract the effects of circulating vasoactive factors. During pregnancy, large amounts of hormones are secreted from the placenta, ...

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“…Stroke volume and heart rate increase gradually, along with venous compliance and venous blood volume, whereas systolic and diastolic blood pressures decrease (Thornburg et al 2000). These changes coincide with a redistribution of blood flow from some maternal organs to the uterus and placenta (Buelke-Sam et al 1982, Dowell & Kauer 1997. Evidence from the infusion of high doses of NKB into female rats would indicate that NKB might be involved in some of these haemodynamic events.…”

mentioning

confidence: 95%

“…Such a mechanism would not need to be switched on permanently; indeed, most normotensive pregnancies showed low or not detected levels of NKB. Nevertheless, it is apparent that the activation of NK3 receptors by NKB could reduce the blood flow through the liver, satisfying the needs of the uterus and placenta; indeed, in rats (Buelke-Sam et al 1982) and rabbits (Nuwayhid 1979) cardiac output to the liver is consistently reduced throughout gestation. We were particularly interested to note that four women with normotensive pregnancies between weeks 9 and 14 had concentrations of NKB equivalent to the highest values that we found at term.…”

mentioning

confidence: 99%