Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhibition of the Na+-K+ active transport system has been postulated to be one mechanism through which myocardial contractility is increased. Rubidium is one substance which has been shown to increase the contractility of guinea-pig atria and inhibit the activity of the isolated Na+,K+-adenosine triphosphatase of guinea-pig ventricle. A reexamination of these results confirmed the positive inotropic effect of rubidium on guinea-pig atria and demonstrated that this effect on contractility is accompanied by a decrease in both resting potential and action potential duration. However, it was also found that rubidium produced a transient negative inotropic effect in guinea-pig ventricle. The latter response was closely paralleled by a transient shortening of action potential duration. A concentration of rubidium maximally effective in decreasing contractility (2.0 mM) had no effect on the slow response action potential or contraction. RbCl (0.1 mM) had no effect on cyclic adenosine 3':5'-monophosphate levels of the ventricle or atrium. RbCl did inhibit active transport in the ventricle, as evidenced by a significant reduction in the electrogenic contribution on the active transport system to the maximal diastolic membrane potential during high-frequency drive. These results demonstrate that RbCl has different effects on the contractility of atrial and ventricular muscle. They also suggest that inhibition of the sodium pump is not necessarily accompanied by an increased force of myocardial contraction.
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PMID:Effects of rubidium on contractility and sodium pump activity in guinea-pig ventricle. 627 Mar 15

Considerable, but as yet still controversial evidence indicates the presence, in mammalian tissues of endogenous digitalis-like factors (EDLFs) which inhibit cell membrane Na+, K(+)-adenosine triphosphatase (Na+, K(+)-ATPase) and which may cross-react with anti-digitalis antibodies. The aim of this study was to evaluate the effect of antibodies against cardiac glycosides on Na+, K(+)-ATPase in human erythrocytes. For this purpose, we measured the effect of antibodies against two different cardiac glycosides (anti-ouabain rabbit antiserum and anti-digoxin Fab fragments) on the activity of the Na+, K(+)-ATPase, as measured by erythrocyte rubidium-86 (86Rb) uptake, in subjects who had never come into contact with exogenous cardiac glycosides, and compared these results with the effect of two control rabbit sera: a normal serum and an antiserum to a non-related antigen. Anti-ouabain rabbit antiserum and anti-digoxin Fab fragments induced a significantly greater percentage change in 86Rb uptake in the erythrocytes than the two control sera (ANOVA followed by multiple comparison by the Games-Howell test). The average percentage change was +11.8 +/- 16.3% (n = 19) (mean +/- SD) for anti-ouabain antiserum +10.8 +/- 15.6% (n = 23) for anti-digoxin Fab fragments, -1.68 +/- 11.2% (n = 11) for anti-rhGM-CSF antiserum, and -5.8 +/- 11.7 (n = 10) for normal control serum. In a subgroup of ten subjects in whom the 3 antisera were tested simultaneously, the stimulation of erythrocyte 86Rb uptake induced by the two antidigitalis antibodies correlated significantly (r = 0.906, p = 0.001, n = 10).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The stimulatory effect on human erythrocyte rubidium-86 uptake by anti-cardiac-glycoside antibodies. 857 8

The aim of the present study was to elucidate whether Chinese traditional herbal drugs, Gorei-San (TJ-17) and Toki-Shakuyaku-San (TJ-23), affect airway smooth muscle tone and, if so, to determine what the mechanism of action is. Rabbit tracheal segments were isolated and the contractile responses to electrical field stimulation and acetylcholine were measured before and after the application of TJ-17 or TJ-23 under isometric conditions in vitro. Ouabain-sensitive rubidium-86 (86Rb) uptake by tissues in response to each drug was also measured. Each herbal medicine attenuated the contractile responses to electrical field stimulation and acetylcholine in a concentration-dependent manner, the maximal inhibition of acetylcholine-induced contraction being 37.5+/-4.9% for TJ-17 and 42.4+/-5.3% for TJ-23 (p<0.05 for each). These effects were not altered by mechanical removal of the epithelium, indomethacin, the nitric oxide synthase inhibitor NG -nitro-L-arginine methyl ester, the cyclic adenosine monophosphate (cAMP)-dependent protein kinase inhibitor adenosine 3'5'-cyclic monophosphorothioate (Rp-cAMPS), the cyclic guanosine monophosphate (cGMP)-dependent protein kinase inhibitor KT5823, or the calcium (Ca2+)-activated potassium (K+) channel inhibitor charybdotoxin, but were greatly inhibited in the presence of the sodium (Na+)-K+ adenosine triphosphatase (ATPase) inhibitor ouabain. Incubation of tissues with TJ-17 and TJ-23 dose dependently increased ouabain-sensitive 86Rb uptake. The results of the study suggest that both Gorei-San and Toki-Shakuyaku-San reduce airway smooth muscle tone via a postjunctional mechanism probably through stimulation of the sodium pump and the subsequent hyperpolarization/repolarization of the cell membrane. These effects may contribute to the antiasthmatic properties of these herbal medicines.
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PMID:Inhibition of airway smooth muscle tone by Chinese herbal medicines. 1129 17


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