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. 1993 Nov;110(3):1184–1188. doi: 10.1111/j.1476-5381.1993.tb13939.x

Nitric oxide-mediated changes in vascular reactivity in pregnancy in spontaneously hypertensive rats.

Z M Chu 1, L J Beilin 1
PMCID: PMC2175808  PMID: 8298807

Abstract

1. To examine the mechanisms which may account for pregnancy-induced vasodilatation in spontaneously hypertensive rats (SHR), we have investigated the changes in vascular reactivity and the effects of endothelial nitric oxide (NO) inhibition in the in situ blood-perfused, mesenteric resistance vessels of 18-20 day pregnant SHR. The effects of NG-nitro-L-arginine (L-NOARG) were compared in pregnant and nonpregnant SHR and gestation matched normotensive Wistar-Kyoto (WKY) rats. 2. Intra-arterial mean blood pressures (MBP) were similar in pregnant and nonpregnant SHR. Basal perfusion pressures (BPP) were decreased in pregnant compared with nonpregnant SHR. Pregnant WKY had lower MBP and BPP than either pregnant or nonpregnant SHR. 3. Vasoconstrictor responses to electrical stimulation (ES) and intra-arterial noradrenaline (NA) were decreased in pregnant compared with nonpregnant SHR. These responses were still greater in pregnant SHR when compared with pregnant WKY. Vascular reactivity to angiotensin II (AII) in pregnant SHR was reduced to a similar level to that in pregnant WKY. 4. L-NOARG (5 mg kg-1, i.v.), an inhibitor of nitric oxide synthase, increased MBP and BPP in all groups. After L-NOARG, BPP were equalized between pregnant and nonpregnant SHR. Pregnant WKY still showed lower MBP and BPP than SHR groups. 5. L-NOARG potentiated vascular responses to ES, NA and AII in all groups. The blunted vascular responses to NA and ES were normalized and the reactivity to AII was only partially reversed in pregnant SHR compared with nonpregnant SHR. Pregnant WKY still had much lower vascular responses to ES and NA than either pregnant or nonpregnant SHR.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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  1. Baylis C., Reckelhoff J. F. Renal hemodynamics in normal and hypertensive pregnancy: lessons from micropuncture. Am J Kidney Dis. 1991 Feb;17(2):98–104. doi: 10.1016/s0272-6386(12)81111-5. [DOI] [PubMed] [Google Scholar]
  2. Broughton Pipkin F., Oats J. J., Symonds E. M. Sequential changes in the human renin-angiotensin system following delivery. Br J Obstet Gynaecol. 1978 Nov;85(11):821–827. doi: 10.1111/j.1471-0528.1978.tb15836.x. [DOI] [PubMed] [Google Scholar]
  3. Chu Z. M., Beilin L. J. Mechanisms of vasodilatation in pregnancy: studies of the role of prostaglandins and nitric-oxide in changes of vascular reactivity in the in situ blood perfused mesentery of pregnant rats. Br J Pharmacol. 1993 Jun;109(2):322–329. doi: 10.1111/j.1476-5381.1993.tb13573.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Jackson E. K., Campbell W. B. The in situ blood perfused rat mesentery; a model for assessing modulation of adrenergic neurotransmission. Eur J Pharmacol. 1980 Aug 29;66(2-3):217–224. doi: 10.1016/0014-2999(80)90145-4. [DOI] [PubMed] [Google Scholar]
  5. Kawasaki H., Saito A., Takasaki K. Age-related decrease of calcitonin gene-related peptide-containing vasodilator innervation in the mesenteric resistance vessel of the spontaneously hypertensive rat. Circ Res. 1990 Sep;67(3):733–743. doi: 10.1161/01.res.67.3.733. [DOI] [PubMed] [Google Scholar]
  6. Lorenz R. P., Picchio L. P., Weisz J., Lloyd T. The relationship between reproductive performance and blood pressure in the spontaneously hypertensive rat. Am J Obstet Gynecol. 1984 Nov 1;150(5 Pt 1):519–523. doi: 10.1016/s0002-9378(84)90431-9. [DOI] [PubMed] [Google Scholar]
  7. Lüscher T. F., Vanhoutte P. M. Endothelium-dependent contractions to acetylcholine in the aorta of the spontaneously hypertensive rat. Hypertension. 1986 Apr;8(4):344–348. doi: 10.1161/01.hyp.8.4.344. [DOI] [PubMed] [Google Scholar]
  8. Matthews J. N., Altman D. G., Campbell M. J., Royston P. Analysis of serial measurements in medical research. BMJ. 1990 Jan 27;300(6719):230–235. doi: 10.1136/bmj.300.6719.230. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Molnár M., Hertelendy F. N omega-nitro-L-arginine, an inhibitor of nitric oxide synthesis, increases blood pressure in rats and reverses the pregnancy-induced refractoriness to vasopressor agents. Am J Obstet Gynecol. 1992 May;166(5):1560–1567. doi: 10.1016/0002-9378(92)91634-m. [DOI] [PubMed] [Google Scholar]
  10. Paller M. S. Mechanism of decreased pressor responsiveness to ANG II, NE, and vasopressin in pregnant rats. Am J Physiol. 1984 Jul;247(1 Pt 2):H100–H108. doi: 10.1152/ajpheart.1984.247.1.H100. [DOI] [PubMed] [Google Scholar]
  11. Yong E. M., Mano M. T., Head R. J. Neurovascular function during pregnancy in the spontaneously hypertensive rat. Clin Exp Pharmacol Physiol. 1992 Jun;19(6):415–423. doi: 10.1111/j.1440-1681.1992.tb00484.x. [DOI] [PubMed] [Google Scholar]

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