Effects of ouabain and potassium-free solution on the contraction of isolated blood vessels
66
Citation
13
Reference
10
Related Paper
The effect of ouabain (10(-5) M) on the Ca2+-evoked phasic contraction was examined in various depolarized vas deferens of the guinea-pig. Ouabain-induced potentiation of the contraction occurred in muscle depolarized with 40 mM K+, but not in muscle depolarized with 0 mM or 137 mM K+. Furthermore, this potentiating effect of ouabain was investigated in the presence of Mn2+ and Mg2+, each of which has an inhibitory effect on Ca2+-contraction. It was strongly inhibited by Mn2+, but unaffected by Mg2+. From these findings it is suggested that ouabain facilitates Ca2+-entry, which is accompanied by the spike generation.
Vas deferens
Cite
Citations (3)
Physarum
Protoplasm
Cite
Citations (11)
Potassium and sodium fluxes in frog muscles incubated in K- and Na-free Mg2+ or choline-substituted Ringer solution were studied. Ouabain (10(-4) M) increased the potassium and decreased the sodium efflux. It was shown, that the increase of the potassium efflux was not due to changes in membrane electrical properties of inhibition of "back pumping" of potassium ions leaking out of the cells. It is supposed that potassium ions are translocated by K-carrier phosphorylated with inorganic phosphate. As known, ouabain accelerates this type of phosphorylation, that is why the potassium efflux increases. In a medium with or without ouabain sodium ions are translocated by Na-ATPase without participation of external potassium ions. Thus sodium and potassium fluxes carried out by membrane ATPase systems are not coupled.
Efflux
Choline
Cite
Citations (1)
Cite
Citations (66)
Objective To characterize ouabain-like immunoreactivity in human urine Methods Sensitive radioimmunoassay for ouabain characterized by high- performance liquid chromatography Results Serial dilution of urinary immunoreactive ouabain paralleled the standard curve, but not so plasma immunoreactive ouabain. Intravenous administration of 86nmol (62.5 μg) ouabain caused a rapid rise in ouabain immunoreactivity in plasma of healthy volunteers with a maximum of 1.7nmol/l 8min after injection and returned to basal levels after 6 h. Ouabain immunoreactivity rose to 36 nmol/l in urine, suggesting that exogenously administered ouabain can be measured reliably in plasma and urine. Analytical reversed-phase high-performance liquid chromatography (isopropanol-propanol biphasic gradient; linear acetonitrile gradient) of sample extracts before assay demonstrated measurable amounts of ouabain-related material only in native urine, but not in plasma. When plasma and urine were spiked with ouabain standard or normal volunteers were injected with ouabain, the assay reliably measured ouabain Conclusion: A substance closely related to ouabain can be detected in urine, but circulates, if at all, in small amounts in human plasma
Cite
Citations (17)
Strophanthin
Cite
Citations (13)
Cardiac glycoside
Cite
Citations (1)
Effects of ouabain (10-12M to 10-5M) on the simultaneously recorded transmembrane action potential and contraction; and (Na+-K+)-activated membrane ATPase of human papillary muscles were investigated. Ouabain in the concentration of 10-12M did not affect the transmembrane potential, contraction and (Na+-K+)-ATPase activity. Ouabain in the concentrations of 10-11 to 10-7M produced a concentration dependent inhibition of (Na+-K+)-APTase associated with shortening of action potential duration and increase in contraction. Ouabain (10-7M) produced a time dependent inhibition of the (Na+-K+)-ATPase associated with the shortening of action potential duration and increase in contraction. Ouabain in the concentration of 10-5M produced an initial marked increase in contraction which was shortly followed by a decrease in contraction and an increase in tone. The muscles developed contracture within 15 to 20min. This concentration of ouabain inhibited the (Na+-K+)-ATPase completely. These results suggest that there is a relation between the inhibition of the (Na+-K+)-ATPase and shortening of action potential duration associated with an increase in contraction. Human papillary muscles seem to be very sensitive to the effect of ouabain.
Cite
Citations (10)
Circulating inhibitor of Na+, K+-ATPase and ouabain-like immuno-reactivity were studied in patients with essential hypertension. In the plasma of patients, two types of Na+, K+-ATPase inhibitors (ouabain-like and non-ouabain-like inhibitors) and ouabain-like immunoreactivity were detected. Ouabain-like inhibitor was clearly detected at a low KC1 concentration (0.1 mM) in the assay buffer, and non-ouabain-like inhibitor was detected at a high KC1 concentration (10 mM). The plasma level of ouabain-like inhibitor correlated significantly with that of ouabain-like immunoreactivity (p<0.001) and with a mean blood pressure (p<0.01). The plasma level of non-ouabain-like inhibitor was not correlated with the levels of either ouabain-like immunoreactivity or mean blood pressure. The level of plasma ouabain-like inhibitor did not correlate with that of plasma non-ouabain like inhibitor. Both ouabain-like inhibitor and ouabain-like immunoreactivity in the plasma of patients with essential hypertension were significantly higher than those in normotensive subjects, but the plasma level of non-ouabain-like inhibitor in patients with essential hypertension was not higher than that in normotensive subjects. These results suggest that the plasma from patients with essential hypertension contains ouabain-like factor(s) which is important to mantain the high blood pressure.
Essential hypertension
Cite
Citations (31)
The nationally-recognized Susquehanna
Chorale will delight audiences of all
ages with a diverse mix of classic and
contemporary pieces. The ChoraleAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂs
performances have been described
as AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂemotionally unfiltered, honest
music making, successful in their
aim to make the audience feel,
to be moved, to be part of the
performance - and all this while
working at an extremely high
musical level.AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA Experience choral
singing that will take you to new
heights!
Cite
Citations (0)