Effects of newly synthetized isoquinoline derivatives on rat uterine contractility and ROCK II activity.

Protein kinases have an important role in signal transduction in the cellular system via protein phosphorylation. RhoA activated Rho-kinases have a pivotal role in the regulation of smooth muscle contraction. ROCK I and ROCK II phosphorylate myosin-phosphatase and myosin-kinase, which induces contraction in the myometrium.

Alteration in expressions of RhoA and Rho-kinases during pregnancy in rats: their roles in uterine contractions and onset of labour.

Activation of RhoA and Rho-associated kinases (ROCKs) is known to play a pivotal role in the regulation of smooth muscle contraction via phosphorylation of myosin-light chain and myosin phosphatase. There are few data on the RhoA and ROCKs expression levels in rat uteri. Therefore, our aim was to investigate the mRNA and protein concentration of RhoA and ROCKs in rat uterus during pregnancy, during parturition and post-partum using real time PCR and Western blot analysis.

The Effects of Female Sexual Hormones on the Expression of Aquaporin 5 in the Late-Pregnant Rat Uterus.

Thirteen mammalian aquaporin (AQP) water channels are known, and few of them play a role in the mammalian reproductive system. In our earlier study, the predominance of AQP5 in the late-pregnant rat uterus was proven. Our current aim was to investigate the effect of estrogen- and gestagen-related compounds on the expression of the AQP5 channel in the late-pregnant rat uterus.

Long-term pretreatment with desethylamiodarone (DEA) or amiodarone (AMIO) protects against coronary artery occlusion induced ventricular arrhythmias in conscious rats.

The aim of this investigation was to compare the effectiveness of long-term pretreatment with amiodarone (AMIO) and its active metabolite desethylamiodarone (DEA) on arrhythmias induced by acute myocardial infarction in rats. Acute myocardial infarction was induced in conscious, male, Sprague-Dawley rats by pulling a previously inserted loose silk loop around the left main coronary artery. Long-term oral pretreatment with AMIO (30 or 100 mg·(kg body mass)(-1)·day(-1), loading dose 100 or 300 mg·kg(-1) for 3 days) or DEA (15 or 50 mg·kg(-1)·day(-1), loading dose 100 or 300 mg·kg(-1) for 3 days), was applied for 1 month before the coronary artery occlusion.

ATP-sensitive potassium channels modulate in vitro tocolytic effects of β₂-adrenergic receptor agonists on uterine muscle rings in rats in early but not in late pregnancy.

Aim: To investigate whether ATP-sensitive potassium (K(ATP)) channels modulate the tocolytic effect of β2-adrenergic receptor (β2-AR) agonists (ritodrine and salmeterol) in early-pregnant (day 6) and late-pregnant (day 22) rat uterus in vitro, in order to examine the relation between the K(ATP) channel sulphonylurea-binding regulatory subunit (SUR) expression and pharmacological reactivity of β2-AR agonists.

Methods: The tocolytic effects of ritodrine and salmeterol (10(-10)-10(-5) M) on spontaneous rhythmic contractions were investigated cumulatively, alone, or in the presence of the K(ATP) channel blocker glibenclamide (10(-6) M) and the K(ATP) channel opener pinacidil (10(-9)-10(-7) M) after 5-min preincubation.

Results: β2-AR agonist induced myometrial relaxation was inhibited by glibenclamide and enhanced by pinacidil on day 6, when SUR1 expression levels were high.