The effect of diphenylhydantoin on LD 50 of ouabain was investigated in frogs, using "one hour frog method". LD50 of ouabain in control group was 1.90 microg/10g. A dose of 100 microg/10g diphenylhydantion did not affect the systemic manifestations of the frogs, but increase the LD50 of ouabain to 2.60 microg/10g. The difference of LD50 of ouabain and potency ratio between control group and diphenylhydantoin-treated group was statistically significant.
Lethal Dose 50 ; Ouabain* ; Phenytoin*

ID clarify the effects of ouabain on the ERG c-wave, isolated chick retinas were exposed to different concentrations of ouabain and the results noted. Although the c-wave was abolished at a highe. dose of ouabain (10(-4)M), its amp1itude increased in the presence of ouabain at a concentration of 10(-7)M, which was within the range of clinical use of the cardiac glycoside. On the other hand, the standing potential of the retina did not change appreciably until 10(-6)M and then decreased gradually at higher concentrations.In the presence of 10(-4)M ouabain, the concentration which completely blorked Na-K-ATPase, both the c-wave and the standing potential were almost abolished. These phenomena were more conspicuous when ouabain was applied to the vitreous side rather than the choroidal side. In the presence of 10(-7)M ouabain, the light sensitivity of the retina was elevated to 0.5 log unit and the maximum response increased about 30%. This may be a sign of visual complications of ouabain, such as metachromatopsia.
Animals ; Chickens ; Electroretinography ; Ouabain/*pharmacology ; Photic Stimulation ; Retina/*drug effects

It has been reported that ascorbic acid[AA]appears to be actively taken up by the corneal endothelium and protect the endothelium against harmful effects of the oxidative reactions. To investigate the effect of ascorbic acidon the corneal endothelial function, rabbit`s corneas were mounted in the in vitro specular microscope. Corneal endothelium was perfused with ascorbic acid, then switched to AA plus ouabain solution, and vice versa. Also, phloretin was perfused onto the endothelium with AA and ouabain. Andcorneal endothelium was perfused with GBR or AA solution followed by perfusion with ouabain. Corneal thickness was measured during the perfusion and the corneal swelling rate calculated. Corneal endothelial permeability was also measured after perfusion of ascorbic acid. Perfusion with AA showed no corneal swelling, but swelling rate was even lower than GBR control. Corneal endothelial permeability did not change upon AA perfusion. In corneas preperfused with ouabain, AA added to ouabain solution decreased corneal swelling rates induced by ouabain solution[19.9 vs. 40.5 micrometer/hr]. The corneas preperfused with AA also showed decreased swelling rates with subsequent perfusion of ouabain added to AA solution[21.7 vs.28.6 micrometer/ hr]. Phloretin inhibited the effect of AA.However, when ouabain was removed, the corneal swelling plateaued but did not return to baseline thickness in both AA and GBR perfusion.The results of this study showed that AA can increase corneal endothelial pump function and reduce corneal swelling caused by ouabain.
Ascorbic Acid* ; Cornea ; Endothelium ; Endothelium, Corneal ; Ouabain ; Perfusion ; Permeability ; Phloretin

OBJECTIVE: The oligosaccharide moieties of glycoproteins and proteoglycans have a vital function in blastocyst differentiation. Concanavalin (ConA), a lectin, is known to bind on the preimplantation embryos, especially on blastocyst. In this study, we investigated whether ConA can modulate the trophoblast development and about the regulating mediator. Also, we investigated whether expansion is enough for hatching procession of the mouse blastocyst. METHOD: Embryos were collected at 72 h post hCG injection and chemicals were treated after 24 h (96 hr post hCG injection). ConA or calcium ionophore A23187 were exposed to blastocyst and than analysis the developmental process for 48 hr. Intracellular free-Ca2+ concentration in trophectoderm was measured with confocal laser microscope after exposing to ConA or calcium ionophore A23187. ConA-pretreated blastocyst exposed to the calcium ionophore A23187 and then analyzed the developmental process. Otherwise ouabain was treated to the blastocyst to block the Na+/K+-ATPase activity. RESULTS: In contrast to the control blastocyst, the ConA-exposed blastocysts developed beyond the expansion stage with significantly high rate (90.4%) at 12 h post administration. ConA induced an increase the intracellular Ca2+ concentration in trophectoderm. Calcium ionophore A23187 also stimulated expansion of blastocyst. Most of the control blastocysts developed to the hatching stage at 144 h post hCG injection. However, strongly 65% of the ConA-exposed embryos were arrested at expanded stage at same time point. The developmental progression rates to hatching stage of both ConA- and calcium ionophore A23187-expose blastocysts were significantly lower than that of the control. However ConA-pretreated embryos developed to the hatching stage like control embryos. Ouabain showed a tendency to delayed the progress to expansion stage but did not inhibit the development to the hatching stage. CONCLUSION: ConA-mediated expansion is the result of the increase of intracellular free-calcium in blastocyst stage embryo. It is suspected that expansion of the blasocyst is a essential indirect factor in hatching and the calcium may triggering the cellular mechanisms for the both expansion and hatching progression.
Animals ; Blastocyst* ; Calcimycin ; Calcium* ; Concanavalin A* ; Embryonic Structures ; Glycoproteins ; Mice* ; Ouabain ; Proteoglycans ; Trophoblasts

Effect of Ouabain administration on aqueous humor dynamics were studied in albino rabbits. Intravenous injection of 0.1 mg/kg of ouabain in 10 rabbits produced significant reduction of intraocular pressure. The highest lowering of intraocular pressure occurred 70 minutes after the injection, its magnitude being 35.54% of the original pressure. The intraocular pressure returned to its original pressure 117.0 minutes after the injection. Perilimbal suction cup studies revealed 26.92 % reduction in aqueous flow. Intravitreal injection of O.1 micro gram of ouabain dissolved in 0.02 ml performed in 5 rabbits' eyes produced marked lowering of intraocular pressure. The maximum tension lowering effect (60.15%) was observed 4.6 days after the administration, and the tension recovered 15.8 days after the injection. Perilimbal suction cup studies showed 29.48 % reduction in aqueous flow. It is concluded that Na-K ATPase play an important role in the aqueous formation and that ouabain lowers the intraocular pressure by supressing this enzyme. Intravitreal administration has more powerful tension-lowering effect than intravenous injection.
Adenosine Triphosphatases ; Aqueous Humor ; Injections, Intravenous ; Intraocular Pressure* ; Intravitreal Injections ; Ouabain* ; Rabbits* ; Suction

BACKGROUND AND OBJECTIVES: Controversy exists regarding the role of endogenous ouabain in the pathogenesis of DOCA-salt induced hypertension. The purpose of this study was to investigate the role of endogenous ouabain in the development of hypertension in DOCA-salt rats. MATERIALS AND METHODS: The mean blood pressure and heart rate were recorded in 1, 2 and 4 week old control and DOCA-salt treated rats. The endogenous levels of ouabain in the plasma, hypothalamus, pituitary and adrenal glands of the 1, 2 and 4 week old control and DOCA-salt treated rats were also measured using a radioimmunoassay. RESULTS: The mean blood pressures in the 2 and 4 week old DOCA-salt treated rats were significantly higher than those of the controls. There was no significant change in the heart rate between the DOCA-salt treated and control groups. In the 4 week old DOCA-salt treated rats, the endogenous level of ouabain in the adrenal glands was higher than that in the control rats, but this was only weakly significant. The endogenous level of ouabain in the hypothalamus was significantly higher in the 1 week old DOCA-salt treated rats than in the control, but this significance disappeared in the 2 and 4 week old DOCA-salt treated rats. CONCLUSION: These results suggest that the endogenous level of ouabain contributes to the development and maintenance of high blood pressure in DOCA-salt rats. Further studies will be required to elucidate the relationship between the endogenous level of ouabain and DOCA-salt hypertension.
Adrenal Glands ; Animals ; Blood Pressure ; Heart Rate ; Hypertension ; Hypothalamus ; Ouabain* ; Plasma ; Radioimmunoassay ; Rats*

Intracellular ions which have a major role in cellular function have been reported to affect repair of radiation damage. Recently it has been reported that ouabain sensitizes A549 tumor cells hut not CCL-120 normal cells to radiation. Ouabain inhibits the Na+-K+-pump rapidly thus it increases intracellular Na concentration. Vanadate which is distributed extensively in almost all living organisms in known to be a Na+-K+-ATPase inhibitors. This study was performed to see any change in radiosensitivity of tumor cell by vanadate and any role of Na+-K+-ATPase in radiosensitization. Experiments have been carried out by pretreatment with vanadate in human cell line(A549, JMG) and mouse cell line(L1210, spleen). For the cell survival MTT assay was performed for A549 and JMG cell and trypan blue dye exclusion test for L120, and spleen cells. Measurements of Na+-K+-ATPase activity in control, vanadate treated cell, radiation treated cell (9 Gy for A549 and JMG, 2 Gy for L1201, spleen), and combined 10-6 M vanadate and radiation treated cells were done. The results were summarized as follows. 1. L1210 cell was most radiosensitive, and spleen cell and JMG cell were intermediate, and A549 cell was least radiosensitive. 2. Minimum or cytotoxicity was seen with vanadate below concentration of 10-6 M. 3. In A549 cells there was a little change in radiosensitivity with treatment of vanadate. However radiation sensitization was shown in low dose level of radiation i. E. 2-Gy. In JMG cells no change in radiosensitivity was noted. Both L1210 and spleen cell had radiosensitization but change was greater in tumor cell. 4. Na+-K+-ATPase activity was inhibited significantly in tumor cell by treatment of vanadate. 5. Radiation itself inhibited Na+-K+-ATPase activity of tumor cell with high Na+- K+-ATPase concention. Increase in radiosensitivity by vanadate was closely associated with original Na+-K+-ATPase contents. From the above results vanadate had little cytotoxicity and it sensitized tumor cells to radiation. Inhibitory effect of vanadate on Na+-K+-ATPase activity might be one of the contributing factors for radiosensitization to tumor cells which has greater enzyme activity than that of normal cell. It was suggested vanadate could be used as a potential radiosensitizer for tumor cells.
Animals ; Cell Survival ; Humans ; Ions ; Mice ; Ouabain ; Radiation Tolerance* ; Spleen ; Trypan Blue ; Vanadates*

In single atrial and ventricular cells isolated from the guinea-pig and the rabbit heart, action potentials and membrane currents were recorded by using the whole cell voltage clamp technique. In rabbit atrial cells the repolarization showed two distinctive phases, referred as the early and late phases(early and late plateau phase), but in guinea-pig atrial cells there was a maintained plateau and less distinctive two phases of repolartization. Increasing intracellular sodium or reducing external sodium by replacement with lithium suppressed the late phase of the action potential in rabbit atrial cells and shortened the plateau of action potential in rabbit ventricle and guinea-pig atrial cells. Reducing external sodium decreased Ca-current and late inward current in voltage clamp. Ouabain in the concentration of 10(-5)M shortened the duration of action potential and shifted the holding current level to outward direction, decreased Ca-current and moved late inward current to outward direction. Ryanodine 10(-6)M which is known to be an inhibitor of Ca-release in the intracellular store, suppressed the late phase of action potential in rabbit atrial cells and shortened the plateau of action potential in rabbit ventricular cells. Ryanodine also decreased Ca-current and shifted late inward current to outward direction. It is concluded that an inward current activated by intracellular calcium contributes to the late Phase of the action potential in rabbit atrial cells and to the late plateau in rabbit ventricular cells and in guinea-pig atrial cells. It may be carried by the Na-Ca exchange precess and/or by calcium-activated non-specific channels but preferably Na-Ca exchange machanism.
Action Potentials* ; Calcium ; Heart* ; Lithium ; Membranes* ; Myocytes, Cardiac ; Ouabain ; Ryanodine ; Sodium

Recently it was introduced that panax ginseng enhanced the ATPase activity and antagonized the inhibited ATPase activity induced by some drugs. The author performed this experiment in order to investigate the effects of ouabain, ethyl alcohol, and panax ginseng respectively on the ATPase activity of mitochondrial fraction isolated from the rabbit retina and ciliary epithelium, and in addition the influence of panax ginseng on the Na - K ATPase activity altered by ouabain and ethyl alcohol. The results obtained are summerized as follow: 1. Ouabain inhibited markedly Na+ - K+ ATPase activity of retina and ciliary epitheliumin vitro and on intravenous injection of ouabain. When ouabain was injected into the vitreous, the ATPase activity of the retina was not influenced compared with the ciliary epithelium. 2. In vitro and on intravenous injection, the inhibitory effects of ethyl alcohol on the ATPase activity was lesser marked than with ouabain. 3. Panax ginseng revealed no influence on Na+ - K+ ATPase activity of mitochondria of rabbit retina and ciliary epithelium in vitro and on intravenous injection. 4. The inhibitory effects of ouabain and ethyl alcohol, in their relatively lower concentrations which showed inhibitory effects, was not antagonized by simultaneous administration with ginseng saponin in vitro, and by pretreatment of ginseng ethyl alcohol extract intravenously.
Adenosine Triphosphatases* ; Epithelium* ; Ethanol ; Injections, Intravenous ; Mitochondria ; Ouabain ; Panax* ; Retina* ; Saponins

The Na+ -K+ -activated ATPase is required to maintain osmotic balance and stabilize cell volume. The Na+ -K+ -ATPase has a more direct role in regulating cell volume; it controls the solute concentrations inside the cell, thereby regulating the osmotic forces that can make a cell swell or shrink. The impotance of the Na+ -K+ -ATPase in controlling cell volume is indicated by the observation that animal cells swell, and may burst, if they are treated with ouabain, which, inhibits the Na+ -K+ -ATPase. The present experiment was designed and carried out to determine the effect of verapamil, a calcium blocker, on the activity of Na+ -K+ -ATPase prepared from renal medulla in the normal rabbit. It was reported that verapamil, a well known coronary vasodilator, possessed negative inotropic effects. The mechanism of action of verapamil was initially thought to be due to coronary vasodilation and blockade of myocardial B-adrenergic receptors. 1t was termed such agent calcium antagonist. A derivative of verapamil, D-600, was subsequently shown to block the movement of calcium through the slow channel and thereby after the plateau phase of the cardiac action potential. Verapamil do not directly antagonize the effects of calcium. Rather, it inhibit the entry of ealcium into cells or its mobilization form intracellular stores and, as such, have been termed a calcium channel blocker.
Action Potentials ; Adenosine Triphosphatases* ; Adenosine* ; Animals ; Calcium ; Calcium Channels ; Cell Size ; Gallopamil ; Ouabain ; Vasodilation ; Verapamil*