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Dihydropyridine Ca2+ channel blockers (CCBs) are widely accepted in the treatment of premature labour. Their mechanism of action in tocolysis involves the blockade of L-type Ca2+ channels, influenced by the Ca2+-activated K+ channels, beta-adrenergic receptors (β-ARs) and sexual hormones. In clinical practice, most experience has been gained with the use of(More)
AIMS Our aims were to examine the effects of a simultaneous stimulation of β(2) -adrenergic receptors and inhibition of uterine phosphodiesterases (PDE), in the pregnant rat uterus in vivo and on human uterine tissue in vitro. We also set out to measure cAMP levels and detect the expressions of the isoenzymes PDE4B and PDE4D in human uterine tissue samples.(More)
AIMS The aims of the study were to investigate the effects of nifedipine on potassium chloride (KCl)-evoked rat uterine contractions on different days of pregnancy in vitro, and the alterations in the effects of nifedipine on combination with terbutaline or progesterone. MAIN METHODS In rat myometrial rings taken on different days of pregnancy, rhythmic(More)
The aim of the study was to investigate the roles of α1-adrenoceptor subtypes in the last-day pregnant rat uterus in vitro by the administration of subtype-specific antagonists (the α1A-adrenoceptor antagonist WB 4101 and the α1D-adrenoceptor antagonist BMY 7378) after 17β-estradiol or progesterone pretreatment. In isolated organ bath studies, contractions(More)
Aquaporins (AQPs) are integral membrane channels responsible for the transport of water across a cell membrane. Based on reports that AQPs are present and accumulate in the female reproductive tract late in pregnancy, our aim was to study the expression of AQP isoforms (AQP1, 2, 3, 5, 8, and 9) at the end of pregnancy in rat in order to determine if they(More)
AIM To study the effects of d- and l-limonene on pregnant rat myometrial contractility in vitro, and investigate how these effects are modified by other agents. D- and l-limonene (10(-13)-10(-8) M) caused myometrial contraction in a dose-dependent manner. METHODS Contractions of uterine rings from 22-day-pregnant rats were measured in an organ bath in the(More)
AIMS Reactive oxygen species play a role in the signal transduction of beta-adrenergic receptors. We investigated whether an antioxidant (tocopherol) can reduce the effect of terbutaline in beta-2-adrenergic receptor (β2-AR)-regulated smooth muscles. MAIN METHODS Contractility of the tissues from nonpregnant (trachea) and 22-day-pregnant (myometrium and(More)
The actions of the endogenous peptide nociceptin (PNOC; previously abbreviated as N/OFQ) on the myometrium have not been investigated previously. Our aim was to study the presence and functional role of PNOC in the modulation of uterine contractility in pregnant rats at term. The presence of PNOC and its receptors (OPRL1; previously called NOP) in the(More)
AIM To assess the effect of 17β-estradiol pretreatment on the function and expression of α2- adrenergic receptors (ARs) subtypes in late pregnancy in rats. METHODS Sprague-Dawley rats (n=37) were treated with 17β-estradiol for 4 days starting from the 18th day of pregnancy. The myometrial expression of the α2-AR subtypes was determined by real time(More)
OBJECTIVE We investigated how progesterone and salmeterol modify the effect of nifedipine in an in vivo preterm birth model in rats, and how terbutaline and nifedipine modify the contractions of the isolated human myometrium. DESIGN Experimental animal and human myometrial studies. SAMPLE Twenty-four female Sprague-Dawley rats and 13 human uterine(More)