Pregnancy increases myometrial artery myogenic tone via NOS- or COX-independent mechanisms
| Autor: | Heather L. Mertz, Shelton M. Charles, Delrae M. Eckman, Lorna G. Moore, Charles R. Rosenfeld, Ridhima Gupta, Timothy M. Morgan |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Adult
medicine.medical_specialty Endothelium Physiology Indomethacin Vasodilation Preeclampsia Pregnancy Physiology (medical) Internal medicine medicine Humans Cyclooxygenase Inhibitors Enzyme Inhibitors Kidney biology Translational Physiology business.industry Myometrium Arteries Middle Aged medicine.disease Nitric oxide synthase NG-Nitroarginine Methyl Ester medicine.anatomical_structure Endocrinology Prostaglandin-Endoperoxide Synthases Vasoconstriction biology.protein Female Endothelium Vascular Cyclooxygenase Nitric Oxide Synthase medicine.symptom business |
| Zdroj: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 303:R368-R375 |
| ISSN: | 1522-1490 0363-6119 |
| DOI: | 10.1152/ajpregu.00490.2011 |
| Popis: | Myogenic tone (MT) is a primary modulator of blood flow in the resistance vasculature of the brain, kidney, skeletal muscle, and perhaps in other high-flow organs such as the pregnant uterus. MT is known to be regulated by endothelium-derived factors, including products of the nitric oxide synthase (NOS) and/or the cyclooxygenase (COX) pathways. We asked whether pregnancy influenced MT in myometrial arteries (MA), and if so, whether such an effect could be attributed to alterations in NOS and/or COX. MA (200–300 μm internal diameter, 2–3 mm length) were isolated from 10 nonpregnant and 12 pregnant women undergoing elective hysterectomy or cesarean section, respectively. In the absence of NOS and/or COX inhibition, pregnancy was associated with increased MT in endothelium-intact MA compared with MA from nonpregnant women ( P < 0.01). The increase in MT was not due to increased Ca2+ entry via voltage-dependent channels since both groups of MA exhibited similar levels of constriction when exposed to 50 mM KCl. NOS inhibition ( Nω-nitro-l-arginine methyl ester, l-NAME) or combined NOS/COX inhibition (l-NAME/indomethacin) increased MT in MA from pregnant women ( P = 0.001 and P = 0.042, respectively) but was without effect in arteries from nonpregnant women. Indomethacin alone was without effect on MT in MA from either nonpregnant or pregnant women. We concluded that MT increases in MA during human pregnancy and that this effect was partially opposed by enhanced NOS activity. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|