Dietary influence on maternal vascular function in pregnancy in the rat
Dietary influence on maternal vascular function in pregnancy in the rat
This thesis investigates the effect of a low protein diet (9% casein) on systemic nitric oxide production and vascular function in virgin and pregnant rats.
Systemic nitric oxide (NO) production was assessed through urinary nitrate excretion. Urinary nitrate excretion was reduced on day 18 of gestation on the low protein diet (P = 0.04), although overall the data were inconclusive. To investigate the influence of a 9% casein diet on vascular reactivity, contractile responses to phenylephrine (PE), or acetylcholine (ACh)-mediated relaxation and the contribution of NO to these mechanisms were studied in virgin and pregnant rats. Virgin and pregnant Wistar rats were fed either the 18% casein or 9% casein diets for 18-19 days; in the pregnant rats, the diets were given from day 1 of pregnancy. 3 mm segments of a third-order mesenteric artery (~300 μm in diameter) were excised and mounted on fine tungsten wires on a small vessel myograph. There were no differences in contractile sensitivity to PE in these vessels from virgin (P = 0.6) and pregnant rats (P = 0.3) fed the 18% casein and the 9% casein diet. Significant reductions in the sensitivity to ACh were found in vessels from virgin (P = 0.03) and pregnant (P = 0.02) rats that had consumed the 9% casein diet. Inhibition of cyclooxygenase and NO synthesis with a combination of indomethacin (INDO) and Nω-nitro-L-arginine methyl ester (L-NAME) significantly decreased ACh-induced dilations in all groups, whereas indomethacin alone did not affect the ACh response. In arteries from the virgin rats on the low protein diet there was also a significant reduction in the sensitivity (P = 0.0003) and maximum relaxation (P = 0.009) to the NO donor spermine NONOate (SPN) whereas the vasodilator potency of SPN did not differ between pregnant 18% and 9% casein-fed rats. Mean placental and fetal weights were significantly lower in the rats fed on 9% casein (P < 0.0001 and P = 0.005 respectively).
University of Southampton
Koumentaki, Angeliki
4b165c2f-a213-4616-8c07-482ddea17b7f
2003
Koumentaki, Angeliki
4b165c2f-a213-4616-8c07-482ddea17b7f
Koumentaki, Angeliki
(2003)
Dietary influence on maternal vascular function in pregnancy in the rat.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This thesis investigates the effect of a low protein diet (9% casein) on systemic nitric oxide production and vascular function in virgin and pregnant rats.
Systemic nitric oxide (NO) production was assessed through urinary nitrate excretion. Urinary nitrate excretion was reduced on day 18 of gestation on the low protein diet (P = 0.04), although overall the data were inconclusive. To investigate the influence of a 9% casein diet on vascular reactivity, contractile responses to phenylephrine (PE), or acetylcholine (ACh)-mediated relaxation and the contribution of NO to these mechanisms were studied in virgin and pregnant rats. Virgin and pregnant Wistar rats were fed either the 18% casein or 9% casein diets for 18-19 days; in the pregnant rats, the diets were given from day 1 of pregnancy. 3 mm segments of a third-order mesenteric artery (~300 μm in diameter) were excised and mounted on fine tungsten wires on a small vessel myograph. There were no differences in contractile sensitivity to PE in these vessels from virgin (P = 0.6) and pregnant rats (P = 0.3) fed the 18% casein and the 9% casein diet. Significant reductions in the sensitivity to ACh were found in vessels from virgin (P = 0.03) and pregnant (P = 0.02) rats that had consumed the 9% casein diet. Inhibition of cyclooxygenase and NO synthesis with a combination of indomethacin (INDO) and Nω-nitro-L-arginine methyl ester (L-NAME) significantly decreased ACh-induced dilations in all groups, whereas indomethacin alone did not affect the ACh response. In arteries from the virgin rats on the low protein diet there was also a significant reduction in the sensitivity (P = 0.0003) and maximum relaxation (P = 0.009) to the NO donor spermine NONOate (SPN) whereas the vasodilator potency of SPN did not differ between pregnant 18% and 9% casein-fed rats. Mean placental and fetal weights were significantly lower in the rats fed on 9% casein (P < 0.0001 and P = 0.005 respectively).
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Published date: 2003
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Local EPrints ID: 465255
URI: http://eprints.soton.ac.uk/id/eprint/465255
PURE UUID: 042d4381-2950-480e-960e-91169abe8aaa
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Date deposited: 05 Jul 2022 00:32
Last modified: 16 Mar 2024 20:04
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Author:
Angeliki Koumentaki
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