| Autor: |
Darr, David, Reid, Deborah, Jarecki, Lori, Verhalen, Tamara, Phernetton, Terrance, Rankin, John, Martin, Chester |
| Zdroj: |
Journal of Maternal-Fetal and Neonatal Medicine; 1993, Vol. 2 Issue: 3 p111-116, 6p |
| Abstrakt: |
Twenty-five mid-gestation guinea pigs were studied to determine the nature of spontaneous uterine contractures and elucidate the temporal relationship between blood flow and contractile activity. In the first protocol, 15 mid-gestation guinea pigs with indwelling vascular catheters were studied. Blood flows were measured by radioactive microsphere technique during rest, uterine contracture, and, in six animals, 1 minute after contracture activity. During contracture, maternal blood flow to the placenta closest to the electrode fell to 81.3 ± 5.3% of control (n = 15, P ± .01) and then rose to 130.4 ± 10.2% of control (P ≤ .01) 1 minute after a contracture. The corresponding relationships were also significant for placental vascular resistance and constitute a reactive hyperemic response of the placenta to uterine contracture. No such phenomenon was observed in the more remote placentas on either the ipsilateral or contralateral side.To investigate the nature of contractile activity, electrodes were placed for measurement of uterine electromyogram in ten mid-gestation guinea pigs. Uterine activity was studied in conscious guinea pigs on the day of surgery and 2 days later. Time spent in synchronous activity fell from 72.9 ± 9.8 on the day of surgery to 24-4 ± 8.4% (P ≤ .01) 2 days later; asynchronous contractile activity rose from 13.9 ± 5.9 to 44.6 ± 6.4% (P ≤ .01), respectively. We conclude that in the guinea pig, contractures are often a local phenomenon during mid-gestation and that they exert an influence on local placental blood flows both during and immediately after contracture. |
| Databáze: |
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