Mechanisms of enhanced vascular smooth muscle contraction induced by sickle erythrocyte constituents.

The mechanisms of the increased vascular tone associated with vaso-occlusive crisis of sickle cell disease have not been clearly defined. The goal of the present study was to examine the role of vascular smooth muscle membrane Na+-K+-ATPase enzyme activity as well as nitric oxide synthase inhibition on the contractile responses induced by sickle erythrocyte constituents. 2 mm ring segments of rabbit carotid arterial ring preparations were placed in 20 ml organ baths containing physiological salt solution (PSS) bubbled with 95% O2, 5% CO2, at 37oC and pH 7.

The Malaria-High Blood Pressure Hypothesis: Revisited.

Malaria etiologies with pathophysiological similarities to hypertension currently constitute a major subject of research. The malaria-high blood pressure hypothesis is strongly supported by observations of the increasing incidence of hypertension in malaria-endemic, low- and middle-income countries with poor socioeconomic conditions, particularly in sub-Saharan African countries. Malnutrition and low birth weight with persistent symptomatic malaria presentations in pregnancy correlate strongly with the development of preeclampsia, gestational hypertension and subsequent hypertension in adult life.

Mechanotransduction and Uterine Blood Flow in Preeclampsia: The Role of Mechanosensing Piezo 1 Ion Channels.

There is a large increase in uterine arterial blood flow during normal pregnancy. Structural and cellular adjustments occur in the uterine vasculature during pregnancy to accommodate this increased blood flow through a complex adaptive process that is dependent on multiple coordinated and interactive influences and this process is known as "vascular remodeling." The etiology of preeclampsia involves aberrant placentation and vascular remodeling leading to reduced uteroplacental perfusion.

Vascular Effects of Histamine.

Four subtypes of receptors (H1, H2, H3 and H4) mediate the actions of histamine. In the vascular wall, the effects of histamine are mediated via H1 and H2 receptors and the actions are modulated by H3 receptor subtype located on presynaptic neurones. Alterations in vascular responses to histamine are associated with experimental as well as a human form of hypertension, suggesting a role for histanine in cardiovascular regulation.

Activated Rho/Rho kinase and modified calcium sensitivity in cryopreserved human saphenous veins.

Background: We have shown previously that cryopreservation of human internal mammary arteries activates protein kinase C and enhances intracellular Ca(2+) [Ca(2+)](i). We now present evidence that in human saphenous veins (HSV) cryoinjury is associated with activation of the Rho/Rho kinase signaling pathways and enhanced [Ca(2+)](i).

Methods: HSV were investigated in vitro either unfrozen within 12h after removal or after storage at -196 degrees C in a cryomedium containing 1.

Increased superoxide dismutase and Na+, K+-ATPase activities in aortic strips from potassium-adapted rats: implication for altered vascular reactivity.

The contributions of superoxide dismutase (SOD) and Na(+), K(+)-ATPase to the altered vascular reactivity in potassium-adapted rats were investigated to test the hypothesis that smooth muscle hyperpolarisation may be involved. Isometric contractions to noradrenaline (NA), 5-hydroxytryptamine (5-HT), and relaxations to acetylcholine (ACh), levcromakalim (LEV) and sodium nitroprusside (SNP), were measured in aortic rings from potassium-adapted rats. Pieces of the aortae were also excised from the animals and assayed for SOD and Na(+), K(+)-ATPase.