Pressure-diameter curves of mesometrial arteries of guinea pigs demonstrate a non-muscular, oestrogen-inducible mechanism of lumen regulation
- 23 Downloads
Pressure-diameter curves were determined on mesometrial (uterine radial) arteries obtained from guinea pigs during different stages of ovarian cycle and pregnancy. In order to investigate changes in arterial diameter that are not caused by the vascular musculature, we studied excised arteries that were relaxed by papaverine (40 mg/l).
The pressure-diameter curves were found to be shifted toward wider diameters when the arteries studied were obtained from pregnant, oestrous or oestrogen treated animals (oestradiol benzoate, 10 μg s.c.): the external diameter at 60 mm Hg transmural pressure on the 14th day of pregnancy exceeded the one during dioestrus by 50%. At term, there was a 7-fold increase. During oestrus and 24 h after oestrogen treatment the diameter was 30–40% wider than during dioestrus. Moreover, we found that the diameter measured on excised vessels in the presence of papaverine is the same as the one observed in situ.
We conclude that the mesometrial arteries of guinea pigs possess a muscle-independent mechanism of lumen regulation. The mechanism operates in non-pregnant and pregnant animals. It may be induced by oestrogen and seems to be qualified for long-term lumen regulation during pregnancy. In contrast, dilation by smooth muscle relaxation appears to be of minor importance in mesometrial arteries.
Key wordsUterus Placenta Arteries Vascular resistance Vasodilation Pregnancy Structural dilation Oestrogen
Unable to display preview. Download preview PDF.
- Albert EN (1967) The effect of pregnancy on the elastic membranes of mesometrial arteries in the guinea pig. Am J Anat 120:611–626Google Scholar
- Astwood EB (1939) Changes in the weight and water content of the normal adult rat. Am J Physiol 126:162–170Google Scholar
- Bauer RD, Busse R, Schabert A (1982) Mechanical properties of arteries. Biorheology 19:409–424Google Scholar
- Bell C (1968) Dual vasoconstrictor and vasodilator innervation of the uterine arterial supply in the guinea pig. Circ Res 23:279–289Google Scholar
- Blatchley FR, Donovan BT, Horton EW, Poyser NL (1972) The release of prostaglandins and progestin into the utero-ovarian venous blood of guinea pigs during the estrous cycle and following estrogen treatment. J Physiol (Lond) 223:69–88Google Scholar
- Bolton TB (1979) Mechanisms of action of transmitters and other substances on smooth muscle. Physiol Rev 59:606–718Google Scholar
- Croix D, Franchimont P (1975) Changes in the serum level of the gonadotrophins, progesterone and estradiol during the estrous cycle of the guinea pig. Neuroendocrinol 19:1–11Google Scholar
- Egund N, Carter AM (1980) Adrenergic and cholinergic responses in the uteroplacental vascular bed of the guinea pig. Acta Radiol (Diagn) 21:387–396Google Scholar
- Ellwood DA, Anderson ABM (1981) The cervix in pregnancy and labor. Churchill Livingstone, Melbourne New YorkGoogle Scholar
- Folkow B (1983) “Structural autoregulation” — the local adaptation of vascular beds to chronic changes in pressure. In: Ciba Foundation symposium 100: Development of the Vascular System. Pitman, London, p. 56Google Scholar
- Furchgott RF, Zawadszki JV (1980) The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature 228:373–376Google Scholar
- Garris DR, Mitchell JA (1979) Intrauterine oxygen tension during the estrous cycle in the guinea pig: Its relation to uterine blood volume and plasma estrogen and progesterone levels. Biol Reprod 21:149–159Google Scholar
- Geppert G (1975) Untersuchungen zur Pharmakokinetik von Oestradiol-17β, Oestradiol-Benzoat, Oestradiol-Valerinat und Oestradiol-Undezylate bei der Frau: Der Verlauf der Konzentrationen von Oestradiol-17β, Oestron, LH und FSH im Serum. Thesis, BonnGoogle Scholar
- Ikeda T, Liu O, Danielpour D, Officer JB, Iio M, Leland FE, Sirbasku DA (1982) Identification of estrogen-inducible growth factors (estromedins) for rat and human mammary tumour cells in culture. In Vitro 18:961–979Google Scholar
- Martensson L, Sjoquist PO, Bjellin L, Carter AM (1979) Myoendothelial and placental blood flow responses to ritodrine infusion in the guinea pig. Am J Obstet Gynecol 135:318–321Google Scholar
- Moll W, Künzel W (1971) Blood pressures in the uterine vascular system of anaesthetized pregnant guinea pigs. Pflügers Arch 330:310–322Google Scholar
- Moll W, Espach A, Wrobel K-H (1983) Growth of mesometrial arteries in guinea pigs during pregnancy. Placenta 4:111–124Google Scholar
- Peeters LLH, Grutters G, Martin GB (1980) Distribution of cardiac output in the unstressed pregnant guinea pig. Am J Obstet Gynec 138:1177–1184Google Scholar
- Sjöquist POB, Bjellin L, Carter AM (1977) Blood flow to the genital tract of oestrous and dioestrous guinea-pigs. J Reprod Fert 51:83–86Google Scholar
- Stockard CR, Papanicolaou GN (1917) The existence of a typical oestrous cycle in the guinea pig — with a study of its histological and physiological changes. Am J Anat 22:225–283Google Scholar