• Archives of Pharmacal Research
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• 제10권2호
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• pp.80-87
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• 1987

To get a better insight into the exxistence and the role of a Na-Ca exchange mechanism in smooth muscle, the effect of Na substitution with sucrose on tension development, cellular Ca uptake and $^{45}Ca$ efflux was investigated using isolated cat ileal longitudinal muscle strips. Experimental results were summarized as follows;1) Exposure of the cat ileal longitudinal muscle to Na-free solution induced a contraction, and the magnitude of the contraction increased after incubation of the muscle strips with ouabain ($2{\times10^{-}5}$M) for 1hr. 2) Cellular Ca uptake in Na-free solution increased with an increase in Na content of the Na-loading media, and a linear relationship existed between tissue Na content and cellular Ca uptake for 10 min 3) After tissues were equilibrated in PSS containing $^{45}Ca$ for 2hr, cellular Ca uptake decreased with rising the external Na concentration. 4)Removal of medium Na or inhibition of the Na-K pump decreased the rate of $^{45}Ca$ efflux. These results strongly suggested that Na substitution increases cellular Ca uptake and decreases the rate of $^{45}Ca$ efflux via a Na-Ca exchange mechanism.

• Applied Biological Chemistry
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• 제39권3호
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• pp.189-194
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• 1996

세포의 활성을 좌우하는 세포질내의 칼슘농도 조절기작을 이해하기 위하여, 전갈 Leiurus quinquestriatus hebraeus (Lqh) 에서 얻은 전갈독소의 세포내 칼슘농도 조절기능과 관련된 효소들의 활성변화에 미치는 효과를 조사하였다. 칼슘펌프와 칼슘채널 효소활성은 돼지의 호흡기 상피세포에서 분리된 마이크로솜에서 측정되었으며, 전갈 독소 Lqh는 온전한 마이크로솜 시료의 경우 총 ATPase의 활성을 약 32% 증가시켰고, Triton X-100나 $Ca^{2+}$ ionophore A23187을 처리한 마이크로솜 시료에서는 총 ATPase의 활성을 약 28% 증가시켰다. Lqh 독소에 의한 ATPase의 활성증가는 $Ca^{2+}-ATPase$의 특이적 저해제인 thapsigargin의 처리로 완전히 저해되었으며, 이것으로 전갈독소 Lqh가 마이크로솜에 위치한 $Ca^{2+}-ATPase$의 활성을 특이적으로 증가시킴을 확인할 수 있었다. 이러한 결과는 결국 Lqh 독소가 $Ca^{2+}-ATPase$의 활성화에 의해 마이크로솜의 $^{45}Ca^{2+}$ uptake를 증가시킬 것이라는 예상을 가능하게 하나, 실제로는 Lqh의 처리가 마이크로솜의 $^{45}Ca^{2+}$ uptake를 오히려 약 30% 감소시켰다. 예상되었던 Lqh에 의한 $^{45}Ca^{2+}$ uptake의 증가는 오직 $InsP_3$ 수용체 칼슘채널의 저해제인 Heparin의 존재시에만 얻어졌다. 이것은 Lqh 독소가 $Ca^{2+}-ATPase$의 활성화에 따른 $^{45}Ca^{2+}$ uptake를 증가시킴과 동시에 또한 $^{45}Ca^{2+}$ release를 유발시킴을 의미하며, Lqh 독소는 실제로 $InsP_3$에 의한 칼슘채널 활성화시에 얻어지는 것과 같은 정도의 $^{45}Ca^{2+}$ release를 유발시킴이 확인되었다. 위의 결과들로부터 Lqh독소에는 적어도 두 가지의 활성성분이 포함되어 있음을 알 수 있었고, 그중 하나는 $InsP_3$ 수용체 칼슘채널의 활성을, 다른 하나는 칼슘펌프의 활성을 촉진시킨다는 결론을 얻었다. 현재 Lqh 독소의 활성성분에 대한 화학적, 전기생리학적 특성들이 연구되어지고 있다.

• 한국식품위생안전성학회지
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• 제11권2호
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• pp.83-87
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• 1996

The objective of this study is to investigate the direct effects of green tea catechins(GTC) on vascular smooth muscle tension and 45Ca2+ Uptake in rat aorta. The methods used in this study are isometric tension measurements using physiograph, Lanthanum method for 45Ca2+(2 uCi/ml) uptake measurement in rat aorta. GTC modified tension induced by 40 mM KCl or 1 uM norepinephrine in rat aorta. Low concentrations of GTC(<0.5mg/ml) increased tension by 40 mM KCl or 1 uM norepinephrine, individually. However, high conecentration of GTC(>0.5 mg/ml) inhibiited tension by 40 mM KCl or 1 uM norepinephrine, individually. GTC increased 45Ca uptake induced by 40 mM KCl in a dose-dependent manner. From these results, GTC has the dual actions in vascular smooth muscle in vitro. Low concentrations of GTC augments tension by K or norepinephrine. However, high concentrations of GTC inhibits tension by K or norepinephrine GTC may have Ca2+ channel activation, action, which may result in unphysiological vasodilation by Ca2+ overload in vascular smooth muscle.

• Archives of Pharmacal Research
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• 제6권1호
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• pp.69-73
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• 1983

It was reported from our laboratory that the rate of deterioration of the force of contraction was slower in heart from Panax ginseng extract treated rats. Present investigation was designed to elucidate the mechanism of the slow deterioration of contractility of ginseng treated hearts. Therefore, $^{45}Ca^{2+}$ Uptake by sarcoplasmic reticulum (SR) isolated from ginseng treated rate and control rats was studied. Rate weighing 150-250g were administered orally with ginseng ethanol extract (100mg/kg) for 10 days. Cardiac SR was isolated by differential centrifugation and $^{45}Ca^{2+}$ uptake was assessed by the Millipore method. Freshly isolated SR from treated as well as control animals did not show any differences, but after incubation for 30 and 60 min at 37.deg.C, $^{45}Ca^{2+}$ uptake of control animal SR was found to be greatly depressed. The SR of treated animal possessed a greater degree of resistance to incubation. Thus it can be concluded that ginseng may have an ability to sustain the normal function of the heart by sustaining Ca accumulation by SR involved with the excitationcontraction coupling processes.

• Clinical and Experimental Reproductive Medicine
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• 제18권2호
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• pp.153-162
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• 1991

The present study was undertaken to clarify the role of calcium ion as a factor for the maturation of follicle-enclosed mouse oocytes. Follicles were isolated with two sharp needles under a stereomicroscope from mouse(ICR) ovaries which were treated PMSG 5 IU 45 hours previously. Isolated follicles were cultured for 14-16 hours in an organ culture system at $37^{\circ}C$, 5% $CO_2$ in air and in a 100% humidified incubator by treatment of hCG, EDTA and $^{45}Ca^{++}$. Culture medium was Modified Hank's Balanced Salt Sol. (MHBS) and addition of hCG (human chorionic gonadotropin) was made into two doses level 0.4 IU and 0.8IU from the stock sol. and also $^{45}Ca^{++}$ was treated in the culture medium. To explain the role of calcium, calcium chelating agent EDTA was treated to the culture of the mouse follicle-enclosed oocytes. Two observations were made in the present study; nucleus phase and $^{45}Ca^{++}$ uptake into the oocyte. HCG induced oocyte maturation in the follicle about two folds as much as the control group, whereas there is no difference in oocyte maturation between 0.4 IU and 0.8 IU of hCG. Optimum level of hCG seems to be 0.4 IU/ml in the mouse follicle culture. HCG stimulated $^{45}Ca^{++}$ uptake into the oocyte of the follicles by two folds. $^{45}Ca^{++}$ uptake in the control group is about 2.5 folds in comparison of the EDTA(1.71mM) treated group. However, calcium uptake in the EDTA treated groups tends to increase depending on the decrease of EDTA concentration. These observations suggest that firstly, hCG stimulates maturation of the oocyte of the follicle, secondly, $Ca^{++}$ influx is induced by hCG and thirdly, $Ca^{++}$ influx by the treatment of EDTA decreases as a dosage-dependent process. This $Ca^{++}$ uptake may take place by the changes of permeability which was induced by hCG treatment. That is, $Ca^{++}$ influx may trigger the resumption of oocyte maturation. It is further necessary in the future study how this $Ca^{++}$ uptake is induced by hCG and increases permeability of the follicle and oocyte.

• Clinical and Experimental Reproductive Medicine
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• 제21권3호
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• pp.285-296
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• 1994

Follicular oocytes were released from the graafian follicles of ovaries from 3-4 weeks old mice. The spontaenous maturation of these follicular oocyes was inhibited by the treatment of dbcAMP and progesterone and these oocytes were cultured for 2-8hr in the Modified Hank's balanced salt solution(MHBS). Ethylenediaminetetraaceticacid(EDTA) and calmoudulin antagonist, trifluoperazine (TFP) were treated to the culture medium in order to investigate whether these chemical agents inhibit calcium uptake into the oocyte and oocyte maturation. $^{45}Ca^{2+}$, 10-${\mu}$Ci/ml was added to the culture medium during the culture period. $^{45}Ca^{2+}$uptake into the oocytes was examined whether and when various kind of oocyte maturation inhibiting agents inhibit or stimulate the influx of calcium into oocytes. Dibutyryl cAMP and progesterone decrease $^{45}Ca^{2+}$uptake into the oocytes and synergistic inhibiting effect of dbcAMP and progesterone was prominent at much lower dosages. Calcium uptake into oocytes seems to be higher during first 2 hour culture period rather than next 4hr culture. After 8hr culture, calcium uptake level of the oocytes which GVBD already took place gradually approached to the level of those which were maintained at GV by the treatment of dbcAMP and progesterone. However, $^{45}Ca^{2+}$uptake into the GV maintained oocytes did not change at all even after 8hr culture period. In addition, calcium chelating agent, EDTA inhibited calcium uptake into oocytes as well as nuclear maturation of oocytes. Lower dosage used in the present study did not inhibit calcium uptake as well as oocyte maturation.

• 약학회지
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• 제28권3호
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• pp.129-138
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• 1984

Specific [$^{3}H$] ouabain binding and $Ca^{2+}$ -uptake were measured to elucidate the role of high affinity [$^{3}H$] ouabain binding site in rat cardiac myocytes which contain 65% of rod cells. High affinity [$^{3}$H] ouabain binding site, which is about 3% of total pump sites, with apparent dissociation constant ($K_{D}$) of $1.1{\times}10^{-7}M$ and maximum binding site concentration (Bmax) of 1.2 pmol/mg protein ($1.754{\times}10^{5}cells$) were identified. At the concentration of $10^{-7}M$ to $10^{-4}M$, ouabain produced concentration dependent increase in $Ca^{2+}$-uptake of myocytes. The effect of ouabain on $Ca^{2+}$-uptake was not effected by membrane depolarization (elevated K+ in incubation medium) or verapamil. These results suggest that in rat ventricular myocytes the ouabain receptor complex to high affinity site may increase Na+ - $Ca^{2+}$ exchange across the sarcolemmal membrane by inhibition of Na+, K+ - ATPase.

• 대한수의학회지
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• 제13권1호
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• pp.5-12
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• 1973

Seventy two guinea pigs were divided into 3 groups; 24 each of control, unilateral thyro-parathyroidectomized and bilateral thyro-parathyroidectomized groups. After the intraperifoneal in jection of $16{\mu}Ci$ of radioactive calcium ($^{45}Ca$) $^{45}Ca$ uptake of various organs and tissues were measured at the 8th, 16th, 24th and 36th hours, respectively, 18 animals were slaughtered (6 from each group) each time. The results obtained were as follows: 1. It was shown that each organ and tissue of treated animals had higher $^{45}Ca$ uptake than the control group, and the bilateralectomized group, higher than the unilateralectomized group, generally. However, there were some exceptions of the findings. The unilateralectomized group had higher $^{45}Ca$ uptake than the bilateralectomized group in case of adrenal gland and femur at the 8th hour; adrenal gland and blood at the 16th hour; spleen, pancreas, adrenal gland, femur and skeletal muscle at the 24th hour; and pancreas, femur and skeletal muscle at the 36th hour, respectively. 2. $^{45}Ca$ uptakes of each organ and tissue were also determind with respect to time. The results were varied with each treatment group, but generally the highest uptake was shown at the 8th hour and decreased gradually thereafter. The differences were not, however, statistically significant. 3. Femur had shown the highest $^{45}Ca$ uptake and the next were blood, pancreas, liver, skeletal muscle and spleen respectively, and the least were adrenal gland and liver, even though there were some variations in the results. 4. The differences in $^{45}Ca$ uptake of each organ and tissue for the treatment group were statstically significant as compared with the test of the control group, except the spleen and blood at the 8th hour; liver at the 16th hour; adrenal gland, spleen, pancreas at the 24th hour; and spleen at the 36th hour.

• The Korean Journal of Physiology
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• 제28권1호
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• pp.27-35
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• 1994

We investigated the alterations in basal tone of aortic strips by changing the Ca concentration, basal $^{45}Ca$ uptake and $^3H-nitrendipine$ binding of the single cells of aortic smooth muscles in the spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. While the basal tone of the aortic strips in WKY rats was not affected by alteration of Ca concentration, that in SHR was decreased by the removal of Ca from the bath solution and was recovered by the restoration of Ca to normal levels. This contraction increased in a Ca concentration-dependent manner and reached a maximum at 2 mM Ca. The basal tone of aorta in SHR was suppressed by verapamil $(10^{-6}M)$. The basal tone of aorta in SHR increased about 50% in the strips of endothelial rubbing, compared with that of intact endothelium. Basal $^{45}Ca$ uptake in the aortic single smooth muscle cells of SHR was greater than that of WKY (p<0.01), Specific bindings of $[^3H]nitrendipine$ in the aortic single smooth muscles of SHR and WKY were saturable. The dissociation constant $(K_d)\;was\;0.71{\pm}0.15\;and\;1.18{\pm}0.08nM$ SHR, respectively, and the difference in $K_d$ between two strains was statistically significant (p<0.03). The maximal binding capacity $(B_{max})\;was\;34.6{\pm}3.2\;and\;47.4{\pm}4.3\;fmol/10^6$ SHR respectively, and the difference of $(B_{max})$ between two strains was statistically significant (p<0.05). from the above results, it is suggested that the increase of Ca influx via potential-operated Ca channels and the increase of the number of dihydropyridine-sensitive Ca channels contribute to high basal tone of the aortic strips in SHR.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1996년도 정기총회 및 학술발표회
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• pp.39-39
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• 1996

Extracts were prepared from six different poisonous mushrooms in order to identify biologically active natural ligands. The effects of these extracts were examined on the microsomal $^{45}$ Ca$^{2+}$ uptake and $^{45}$ Ca$^{2+}$ release. Five out of six species apparently inhibited the activity of total microsomal ATPases prepared from the epithelial cells of pig airway. (omitted)ted)