• The Korean Journal of Physiology
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• 제11권2호
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• pp.9-16
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• 1977

The present experiment was conducted to see whether or not several cardioactive agents influence the 'regenerative $Ca^{++}$ release' in the mechanically disrupted cardiac cells. The mechanically disrupted cardiac cells were prepared by the method of Kerrick and Best from the ventricle of rat. The tension development of the disrupted cardiac cells was measured with a mechanoelectric transducer (RCA 5734). The results were summarized as follows 1) 2 mM caffeine enhanced the regenerative $Ca^{++}$ release, whereas 2 mM Procaine inhibited the $Ca^{++}$ release as reported by other investigators. 2) Epinephrine at concentrations of $10^{-7},\;10^{-6}\;and\;10^{-5}M$ increased the regenerative $Ca^{++}$ release significantly but showed a poor dose response on the $Ca^{++}$ release. 3) Propranolol showed no effect on the regenerative $Ca^{++}$ release when studied alone. Furthermore, it showed no antagonistic effect on an increased regenerative $Ca^{++}$ release induced by epinephrine. 4) Other cardioactive agents such as acetylcholine, ouabain, isoproterenol and c-AMP at concentrations of $10^{-6}M$ showed no effect on the regenerative $Ca^{++}$ release. From the above results, it may be concluded that the cardioactive actions of these agents are not related directly to the process of regenerative $Ca^{++}$ release.

• The Korean Journal of Physiology
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• 제1권2호
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• pp.141-150
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• 1967

The present investigation was initially undertaken to see if there exists $Na^+-K^+$ activated ATPase in the microsome fraction of the kidney. Having confirmed the presence of such an enzyme, further attempts have been made to characterize its nature and the following conclusions were obtained: (1) The ATPase activity was greatest at the $Na^+$ concentration of 100 mM as well as at $K^+$ concentration of 10 mM. Moreover, the ATPase activity was found to be depressed by $Ca^{++}$ in the presence of $Mg^{++}$. (2) While the ATPase activity was depressed by Ouabain, the magnitude of inhibition was greater in the Na medium than in the K medium. (3) NaCN augmented the ATPase activity whereas NaF and IAA depressed it. On the other hand, DNP had little influence on the ATPase activity. (4) Diamox, vasopressin and aldosterone had no effect while $HgCl_2$ markedly depressed the ATPase activity These findings indicate that the nature of ATPase isolated from the microsome fraction of the rabbit kidney is quite similar to that from other organs such as the heart and the muscle, although there are certain features specific to the type of organs.

• The Korean Journal of Physiology
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• 제23권2호
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• pp.291-299
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• 1989

Na and Ca effects on contracture were studied in order to estimate Na/Ca exchange ratio in the isolated atrial muscle of the rabbit. All experiments were performed in tris-buffered Tyrode solution which was being aerated with 100% $O_2\;and\;kept\;at\;37^{circ}C$. To load intracellular $Na^+,\;10{-6}M$ ouabain or K-free solution were used. Contractures were induced by brier exposure of atrial muscle to Tyrode solution containing various concentrations of Ca or of Na. The results obtained were as follows: 1 ) Increasing the extracellular Ca concentration, the amplitude of contracture also increased and was maximum at 8 mM Ca-Tyrode solution. 2) The relationship between extracellular Ca concentrations and relative amplitude of the contractures showed hyperbolic pattern. By using Hill plot, the line has the slope of 1 12 which means the number of Ca binding sites of the carrier in the cell membrane. 3) The amplitude of the contracture was maximum in 0 mM Na-Tyrode solution and decreased in dose dependent manner when the Na concentration increased. 4) When the relationship between extracellular Na concentrations and the amplitude of contractures was expressed as dose-response curve, the curve showed sigmoid pattern. The line with the slope of 2.82 was obtained by using Hill plot. 5) From above all the results, it is suggested that exchange ratio of Na and Ca via Na/ca exchange system in the atrial muscle of rabbit could be 3:1 approximately.

• The Korean Journal of Physiology
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• 제8권2호
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• pp.59-66
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• 1974

In recent years much interesting information about the mechanism of the $Na^+-K^+$ activated ATPase has been obtained from investigation of the $K^+-activated$ phosphatase activity which appears to be catalysed by the same enzyme. Also several studies have indicated that a $K^+-activated p-nitrophenylphosphatase activity is intimately related to the ATPase activity. And then the exact relation of p-nitrophenylphosphatase activity to $Na^+-K^+$ ATPase activity is not known. The effects of some ions and drugs on the p-nitrophenylphosphatase activity of the rat brain were investigated and the results were summarized as follows. 1. The p-nitrophenylphosphatase was stimulated markedly by low concentrations of $K^+$, while the activity was activated slightly in the presence of $Na^+$ and oligomycin. 2. Addition of both ATP and $Na^+$ caused a remarkable increase in the activity of the $K^+-dependent$ phosphatase at low concentrations of $K^+$. 3. In the presence of $Na^+$ and low concentrations of $K^+$, oligomycin activated the p-nitrophenylphosphatase. 4. O1igomycin inhibited the stimulation of the enzyme activity caused by $Na^{+}+ATP$. 5. Ouabain inhibited the $K^+-dependent$ p-nitrophenylphosphatase activity more in the presence of ATP and $Na^+$ than in their absence. 6. Quinidine inhibited both $Na^+-K^+$ ATPase and p-nitrophenylphosphatase. These inhibitory effects of the drug were partially antagonized by increasing $K^+$ concentrations. The sensitivity of the $K^+-dependent$ p-nitrophenylphosphatase to quinidine was greater than the that of $Na^+-K^+$ ATPase.

• 대한약리학회지
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• 제26권2호
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• pp.161-166
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• 1990

Kallikrein-kinin계는 신장의 혈류역학과 수분 및 전해질 배설의 조절자로서 역할을 하는 것으로 알려져 있다. Kallikrein-kinin계의 유효한 펩타이드중 하나인 bradykinin(BK)을 신동맥에 주입시 전해질 배설이 증가하는데 이 작용이 신혈류역학적 변동에 기인하는지 또는 신세뇨관의 전해질 운반에 대한 직접적인 작용에 기인하는지 아직 확실치 않다. 따라서 본 연구에서는 원위세뇨관(DT)과 피질집합관(CCT)에서의 전해질운반 의존성 산소소비에 대한 BK의 영향을 관찰하였다. BK$(0.1\;{\mu}M)$은 DT과 CCT의 산소소비를 유의하게 감소시켰으며 이 작용은 Na부재시 나타나지 않았고 ouabain전처치에 의해 차단되었다. 또한 이 작용은 mepacrine에 의해 유의하게 차단되었으며 indomethacin에 의하여는 차단되지 않았다. 이상의 결과는 BK이 DT과 CCT에서 Na운반과 관련한 산소소비를 억제시키며 이 작용에는 prostaglandin들이 관여하고 있지 않음을 시사한다.

• 생약학회지
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• 제37권4호
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• pp.272-277
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• 2006

This study was undertaken to determine whether Juglandis Semen (JAS) extract exerts protective effect against oxidant-induced inhibition of $Na^+-pump$ activity in cerebral cortex. $Na^+-pump$ activity was estimated by measuring ouabain-sensitive oxygen consumption. The oxygen consumption significantly inhibited by 1mM t-butylhydroperoxide (tBHP), which was prevented by addition of 2% JAS extract. The oxygen consumption was increased by an increase in $Na^+$ concentration from 5 to 100 mM, $K^+$ concentration from 0.5 to 10 mM, and $Mg^{2+}$ concentration from 0.2 to 5 mM. These changes in ion concentrations did not affect the inhibitory effect of tBHP and protective action of JAS on oxygen consumption. tBHP (l mM) produced a significant increase in lipid peroxidation in cerebral cortex, which was prevented by 2% JAS extraction. These results suggest that JAS exerts protective effect against tBHP-induced inhibition of $Na^+-pump$ activity in the cerebral cortex, probably through action as antioxidant.

• 환경생물
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• 제18권2호
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• pp.255-262
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• 2000

Synaptosome에 의한 [$^3$H]-serotonin의 일반적인 흡수특성과 이 과정에 납이 미치는 영향을 in vitro와 in vitro에서 관찰하였다. 흰쥐의 대뇌와 뇌간에서 각각 분리한 synaptosome의 흡수친화력은 대뇌가 Km=0.5$\mu$M, 뇌간이 Km=0.1$\mu$M로 모두 고친화성 흡수였고 뇌간에서 더 높았다. 또한 이 흡수과정에 sodium과 potassium이온이 영향을 미치는 것으로 나타났다. Synaptosome이 [$^3$H]-serotonin을 흡수하는 과정은 납에 의해 억제되었고 이러한 납의 독성영향은 in vitro와 in vitro에서 유사한 결과를 보였다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.181-181
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• 1996

The (Na, K) ATPase is a membrane ion transporting ATPase composed of an ${\alpha}$ catalytic subunit and a ${\beta}$ glycoprotein subunit. The topology of the rat ${\alpha}$1 and ${\beta}$1 subunits has been studied by insertion of epitope(s) : at the NH2-terminus and COOH-terminus and between Glu117 and Glul18, Lys828 and Arg829, Gln900 and Trp901, and Va1939 and Phe940 of the ${\alpha}$ subunit; and at the NH2-terminus and COOH-terminus and between Glu228 and Tyr229 of the ${\beta}$ subunit. The epitope-tagged ${\alpha}$l, constructs were expressed in HeLa cells to select for stable cell lines expressing a functional (Na, K)ATPase. All constructs, except for the one tagged between Gln900 and Trp901, resulted in ouabain-resistant colonies indicating that modified proteins retained functional integrity. The epitope-tagged ${\beta}$ constructs were transiently expressed in Cos-7 cells. The orientation of the epitopes with respect to the cell membrane was revealed by indirect immunofluorescence performed on permeabilized and non-permeabilized cells expressing the (Na, K)ATPase chains. The results indicate that the ${\alpha}$ subunit has 4 transmembrane segments in the COOH terminal membrane bound domain between residues 760 and 938, and that both the NH2-terminus and the COOH-terminus are in the cytosol; it was not determined whether there are more transmembrane segments between residue 938 and the COOH-terminus. The ${\beta}$ subunit has only one transmembrane spanning region with the NH2-terminus in the cytosol and the COOH-terminus on the extracytoplasmic surface of the plasma membrane.

• Journal of Pharmaceutical Investigation
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• 제24권3호spc1호
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• pp.49-57
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• 1994

The objective of this study was to determine whether Pz-peptide, an enhancer of hydrophilic solute permeability in the intestine, could elevate the paracellular permeability of the cornea and conjunctiva in the pigmented rabbit. The in vitro penetration of four hydrophilic solutes, mannitol (MW 182), fluorescein (MW 376), FD-4 (FITC-dextran, 4 KDa), and FD-10 (FITC-dextran, 10 KDa) across the pigmented rabbit cornea and conjunctiva was studied either in the presence or absence of 3 mM enhancers. Drug penetration was evaluated using the modified Ussing chamber. The conjunctiva was more permeable than the cornea to all four markers. EDTA and cytochalasin B showed higher effects on marker transport than Pz-peptide, but Pz-peptide elevated the corneal transport of mannitol, fluoresein, and FD-4 by 50%, 26%, and 50%, respectively, without affecting FD-10 transport. Possibly due to the leakier nature of the conjunctiva, 3 mM Pz-peptide elevated the transport of only FD-4 by about 45%, without affecting the transport of other markers. Furthermore, the transport of Pz-peptide itself across the cornea and conjunctiva increased with increasing concentration in the 1-5 mM range, suggesting that Pz-peptide enhanced its own permeability, possibly by elevating paracellular permeability. Effects of ion transport inhibitors on Pz-peptide transport were then investigated. PZ-peptide penetration was not changed by mucosal addition of $10\;{\mu}M$ amiloride or $10\;{\mu}M$ hexamethylene amiloride, inhibiting serosal $Na^{+}$ exit by $100\;{\mu}M$ ouabain, or replacing $Na^{+}$ with choline chloride in the mucosal side buffer. These results seggested that Pz-peptide enhanced the paracellular permeability of rabbit cornea and conjunctiva and further indicate that ion transporters were not involved in the Pz-peptide induced elevation of paracellular marker permeability.

• The Korean Journal of Physiology and Pharmacology
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• 제6권4호
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• pp.225-233
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• 2002

Kanagawa hemolysin (KH), an exotoxin produced from Kanagawa phenomenon-positive Vibrio parahemolyticus, has been shown to possess various biological activities including hemolysis, enterotoxicity, cytotoxicity, and cardiotoxicity. The aim of this study was to investigate the effect of KH on the cardiovascular system and its mechanism, employing in vivo and in vitro experiments of the rat. Intracerebroventricular (icv) administration of 100 mHU KH produced a marked and continuous pressor effect (icv KH-pressor effect), and the icv pressor effect was not repeatable. However, intravenous (iv) injection of the same dose of KH induced a prominent depressor effect (iv KH-depressor effect). The icv KH-pressor effect was inhibited by acid-denaturation, while the iv KH-depressor effect was not. Simultaneous icv administration of the three agents (ouabain, diltiazem, or bumetanide: $10{\mu}g/kg$ each) significantly reduced the pressor effect. The icv KH-pressor effect was inhibited by treatment with iv phentolamine or chlorisondamine, but was not affected by iv candesartan. The iv KH-depressor effect was repeatable and was attenuated by treatment with iv NAME or methylene blue. In vitro experiments using isolated thoracic aorta, $10^{-6}$ M phenylephrine (PE) and 50 mM KCl produced a sustained contraction. In rings contracted with either agents, KH showed relaxant responses in a concentration- dependent fashion and the relaxation (KH-vasorelaxation) was not dependent on the existence of the endothelium. The KH-vasorelaxation in the endothelium-intact rings contracted by PE was abolished by methylene blue treatment. In summary, the present findings suggest that in the icv KH-pressor effect the cation leak-inducing action of KH is implicated, which leads to the increased central sympathetic tone, that the iv KH-depressor effect results from the vasorelaxation via NO-guanylate cyclase system, and that the KH-vasorelaxation is independent of the endothelium and the guanylate cyclase system is involved in it. In conclusion, the mechanism of KH producing the icv pressor effect may not be identical to that of KH producing the iv depressor effect.