Augmented EDHF signaling in rat uteroplacental vasculature during late pregnancy

A successful pregnancy outcome relies on extensive maternal cardiovascular adaptation, including enhanced uteroplacental vasodilator mechanisms. The objective of the present study was to determine the contribution of the endothelium-derived hyperpolarizing factor (EDHF) signaling in pregnancy-enhanced uterine vasodilation, to define the role of Ca(2+)-activated K(+) channels in mediating EDHF effects, and to explore the impact of endothelial Ca(2+) signaling in pregnancy-specific upregulation of EDHF. Fura 2-based measurements of smooth muscle cell (SMC) and endothelial cell cytosolic Ca(2+) concentration ([Ca(2+)](i)) were performed simultaneously with measurements of the diameter of uterine radial arteries from nonpregnant (NP) and late pregnant (LP) rats. Changes in SMC membrane potential of pressurized arteries from LP rats were assessed using glass microelectrodes. After blockade of nitric oxide and prostacyclin production, a cumulative application of ACh induced rapid and effective dilatation of uterine vessels from both NP and LP rats. This vasodilation was associated with SMC hyperpolarization and SMC [Ca(2+)](i) reduction and was abolished by a high-K(+) solution, demonstrating that N(G)-nitro-L-arginine (L-NNA)- and indomethacin-resistant responses are attributable to EDHF. Pregnancy significantly potentiates EDHF-mediated vasodilation in part due to enhanced endothelial Ca(2+) signaling. L-NNA- and indomethacin-resistant responses were insensitive to iberiotoxin but abolished by a combined treatment with apamin and charybdotoxin, supporting the key role of small- and intermediate-conductance K(+) channels in mediating EDHF signaling in the maternal uterine resistance vasculature.

Medienart:

E-Artikel

Erscheinungsjahr:

2010

Erschienen:

2010

Enthalten in:

Zur Gesamtaufnahme - volume:299

Enthalten in:

American journal of physiology. Heart and circulatory physiology - 299(2010), 5 vom: 01. Nov., Seite H1642-52

Sprache:

Englisch

Beteiligte Personen:

Gokina, N I [VerfasserIn]
Kuzina, O Y [VerfasserIn]
Vance, A M [VerfasserIn]

Links:

Volltext

Themen:

115422-61-2
24345-16-2
Apamin
Biological Factors
Charybdotoxin
Cyclooxygenase Inhibitors
EC 1.14.13.39
EC 1.14.99.1
Endothelium-dependent hyperpolarization factor
Indomethacin
Journal Article
Nitric Oxide Synthase
Potassium Channels, Calcium-Activated
Prostaglandin-Endoperoxide Synthases
Research Support, N.I.H., Extramural
XXE1CET956

Anmerkungen:

Date Completed 29.11.2010

Date Revised 20.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1152/ajpheart.00227.2010

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM20135229X