Nitric oxide donor-induced inhibition of pregnant rat uterine spontaneous contractile activity and release of nitric oxide from uterus measured by microdialysis.
Our aim was to study whether nitric oxide (NO) donor-induced inhibition of pregnant rat myometrium contractility correlates with the release of NO. Uterine rings from mid-pregnant and late pregnant Sprague-Dawley rats were used for isometric tension recording. Concentration-response relationships to sodium nitroprusside (SNP), nitroglycerine (NTG) and diethylamine (DEA)/NO were assessed. The time course of NO release after addition to the organ chambers of the 3 NO-donors was assessed by the detection of NO products NOx (NO3+NO2) using the microdialysis probe by a HPLC-NO detector system. DEA/ NO induced greater inhibition of the spontaneous contractile activity of uterine rings from mid-pregnant rats than SNP or NTG. In uterine rings from late pregnant rats, however, the maximal inhibition of the contractility by all 3 NO-donors were significantly less. The NOx levels measured in the uterine ring walls from either mid-pregnant or late pregnant rats significantly increased after DEA/ NO as compared to the basal levels or the levels after NTG or SNP. The decrease of NO-donor-induced inhibition of rat myometrium contractility, with unchanged formation of NOx, at term, suggests that the changes in NO signaling are responsible for gestational age-dependent attenuation of the inhibitory effect.
Department of Obstetrics and Gynecology, Fukushima Medical University School of Medicine, Fukushima, Japan. okawat@fmu.ac.jp
T
T
Okawa
K
K
Asano
H
H
Takahashi
A
A
Sato
Y P
YP
Vedernikov
G R
GR
Saade
R E
RE
Gafield
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004048:Diethylamines / Q000494:pharmacology; D005260:Female; D017551:Microdialysis; D009215:Myometrium / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014590:Uterine Contraction / Q000187:drug effects*
D004048:Diethylamines; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; C034281:diethylamine; D005996:Nitroglycerin