Abstract
Regular, spontaneous contractions of human myometrial strips obtained at the time of elective cesarean section were recorded in a tissue bath in five experiments. Administration of the β-adrenergic agonist isoproterenol (1 μmol/L) resulted in the rapid onset of myometrial relaxation. In the continuous presence of the β-agonist, myometrial contractions of amplitude equal to or greater than that of baseline resumed after 10 to 40 minutes (mean ± SEM = 29.7 ± 7.3), indicating the development of desensitization of the tissue to the tocolytic effects of isoproterenol. In contrast, intermittent exposure of the myometrial strips to isoproterenol prevented the onset of desensitization and resulted in prolonged inhibition of myometrial contractions. These findings suggest that modification of the present regimen of administration of β-adrenergic agonists from continuous to intermittent infusion may improve the success of these agents in the prevention of preterm births.
| Original language | English |
|---|---|
| Pages (from-to) | 841-844 |
| Number of pages | 4 |
| Journal | American Journal of Obstetrics and Gynecology |
| Volume | 149 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Aug 15 1984 |
Bibliographical note
Funding Information:From the Departments of Obstetrics and Gynaecology, Physiology and Biophysics, and Pharmacology, Faculty of Medicine, Dalhousie University. Supported by Medical Research Council of Canada Grant MA-7625, the H. B. Atlee Endowment Fund, and the Dalhousie University Medical Faculty Research Foundation. Received for publication December 13, 1983; accepted March 22, 1984. Reprint requests: Dr. Robert Casper, 339 Windermere Road, Lon-don, Ontario, Canada, N6A 5A5. *Dr. Casper is the recipient of a Medical Research Council Schol-arship.
ASJC Scopus Subject Areas
- Obstetrics and Gynaecology