INCREASE IN 45Ca UPTAKE DURING BARIUM-INDUCED CONTRACTURE IN GUINEA PIG TAENIA COLI

Karaki, Hideaki; Ikeda, Miyoshi; Urakawa, Norimoto

doi:10.1254/jjp.17.496

Cited by 3 publications

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“…Urakawa and Holland (3) reported that hypertonic 40 mm K-induced tension develop ment in taenia coli was composed of phasic and tonic phases and suggested that in the phasic contraction, sufficient Ca is released from a cellular site to initiate contraction, whereas in the tonic contraction enough Ca crosses the membrane to initiate and also to maintain contraction. These data were supported in other reports (2)(3)(4)10). In the present data, the difference in 5th minute values of "Ca uptake and tissue Ca shown in Fig.…”

Section: Discussionsupporting

confidence: 93%

“…In previous publications it was reported that barium in concentrations from 0.5 to 20 mm induced tension development in isolated guinea pig taenia coli, which response was dependent on the presence of external calcium (1), and that total Ca content did not change but 45Ca uptake of the cellular fraction which did not exchange within 4 minutes increased above control level during Ba-induced tension development (2). It was also mentioned that Ba increased Ca entry in taenia coli and that this Ca probably plays an essential role during tension development (2).…”

mentioning

confidence: 92%

“…This work was undertaken to study the movement of Ca in taenia coli during Ba and high-K-induced tension developments by investigating the total Ca, 45Ca uptake and efflux and "Ca uptake of the cellular fraction which did not exchange within 4 minutes. A part of this work has already been reported (2,4).…”

mentioning

confidence: 98%

“…It was also mentioned that Ba increased Ca entry in taenia coli and that this Ca probably plays an essential role during tension development (2).…”

mentioning

confidence: 99%

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Movements of Calcium During Tension Development Induced by Barium and High-Potassium in Guinea Pig Taenia Coli

Karaki

Ikeda

Urakawa

1969

Japanese Journal of Pharmacology

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In previous publications it was reported that barium in concentrations from 0.5 to 20 mm induced tension development in isolated guinea pig taenia coli, which response was dependent on the presence of external calcium (1), and that total Ca content did not change but 45Ca uptake of the cellular fraction which did not exchange within 4 minutes increased above control level during Ba-induced tension development (2). It was also mentioned that Ba increased Ca entry in taenia coli and that this Ca probably plays an essential role during tension development (2).On the other hand, hypertonically added 40 mm K-induced tonic tension develop ment in taenia coli was noted to be composed of phasic and tonic phases and it was proposed that in the phasic contraction, sufficient Ca is released from a cellular site to initiate con traction, whereas in the tonic contraction enough Ca crosses the membrane to initiate and also to maintain contraction(3). However, the movement of Ca in the above processes has not been studied systematically. This work was undertaken to study the movement of Ca in taenia coli during Ba and high-K-induced tension developments by investigating the total Ca, 45Ca uptake and efflux and "Ca uptake of the cellular fraction which did not exchange within 4 minutes. A part of this work has already been reported (2, 4). METHODSStrips of taenia coli isolated from white male guinea pigs were suspended in Tyrode solution of the following composition (mm); NaCI 136.8, KC1 2.7, CaC12 2.5, MgC12 1.0, NaH,PO4 0.4, NaHCO3 11.9 and glucose 5.5, at 37°C, and gassed with 95% 02 and 5% CO, mixture. Ba and high-K Tyrode solutions were made hypertonically by adding BaC1, or KC1 crystals to the medium to give final concentrations of 0.5 and 20 mm Ba and 40 mm K, respectively. Tension changes were recorded isometrically by mechano-elec trotransducer.45Ca uptake: In the first series of experiments , muscles equilibrated for one hour in normally Tyrode solution were incubated in a medium containing 0.5 mm Ba or 40 mm K

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Section: Discussionsupporting

confidence: 93%

mentioning

confidence: 92%

mentioning

confidence: 98%

“…It was also mentioned that Ba increased Ca entry in taenia coli and that this Ca probably plays an essential role during tension development (2).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Movements of Calcium During Tension Development Induced by Barium and High-Potassium in Guinea Pig Taenia Coli

Karaki

Ikeda

Urakawa

1969

Japanese Journal of Pharmacology

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“…It has already been reported that 45Ca uptake and total Ca content of guinea pig taenia coli increased when 40 mm K was added hypertonically to the external medium (1,2).…”

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confidence: 90%

45Ca UPTAKE AND TISSUE Ca OF GUINEA PIG TAENIA COLI IN ISOTONIC HIGH-K/Na-DEFICIENT MEDIUM

Urakawa

Karaki

Ikeda

1968

Japanese Journal of Pharmacology

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It has already been reported that 45Ca uptake and total Ca content of guinea pig taenia coli increased when 40 mm K was added hypertonically to the external medium (1, 2).However, the addition of high-K isotonically, that is, an appropriate concentration of ex ternal sodium replaced by potassium, to depolarize and/or contract smooth muscle prepa rations, is the method that is widely employed.We have reported (3) that in isotonic high-K medium, which contained less Na, smooth muscle of taenia coli showed a shape of contracture different to that shown in hypertonic 40 mm K medium, which contained normal concentration of Na.In the present paper, changes in 45Ca uptake and tissue Ca of guinea pig taenia coli in isotonic 152 mm K/Na deficient medium were studied and the results were compared with those in hypertonic 40 mm K medium. METHODSStrips of taenia coli isolated from male guinea pigs were suspended in an organ bath containing Tyrode solution of the following composition (mm): NaCl, 136.8; KC1, 2.7; CaC12, 2.5; MgC1,, 1.0; NaH2PO4j 0.4; NaHCO3, 11.9; and glucose, 5.5, saturated with 95% 02 and 5% CO2 gas mixture at 37°C. Tension changes were recorded isometrically with Nihon Kohden multi-purpose polygraph.45Ca uptake: After pretrc ~tment , muscle strips were placed in an incubation medium containing 45Ca (1 x 106 counts ,' ainute) ml) for specified intervals with and without elevated K. At the end of each incubation period, the strips were washed three times in 4 minutes with a non-radioactive Tyrode solution of the same composition as the incubation medium, removed from the bath, blotted gently on filter paper and weighed. They were then transferred to quatz tubes to which 0.1 ml HC104 was added. The samples were ashed in a furnace at 550°C, diluted with 0.1 N HC1, pipcttcd into planchettes, dried and radio activity was counted in a gas flow counter (Aloka window type Model PS-13). Data are expressed as counts per minute per kilogram wet weight of muscle. Radioactive 45Ca was supplied by Nuclear Science and Engineering Corp., U.S.A., as the chloride.

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Effects of External Calcium and Some Metabolic Inhibitors on Barium-Induced Tension Changes in Guinea Pig Taenia Coli

1967

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It was reported that the contractions in taenia coli induced by carbachol (1), ACh (2), phosphatidic acid (3) and high-potassium (K) (1,4,5) are all dependent on external calcium.On the other hand, Yukisada and Ebashi (6) have reported that rat, guinea pig, and rabbit ileum and rat uterus respond to barium (Ba) in the absence of external cal cium. These results have been supported by experiments with rat uterus (7).In the first series of experiments in this paper, the relationship between Ba-induced tension development and external calcium was re-examined using isolated taenia coli preparations.K-induced contracture in taenia coli was reported to be composed of two phases, namely, phasic and tonic responses (5, 8). Furthermore, the tonic response was abolished in the presence of various inhibitors of metabolism and active transport (8).The second series of experiments were designed to examine the effect of the above mentioned inhibitors on Ba-induced tension development.Some of the results have already been reported (9). METHODSStrips of taenia coli were isolated from male guinea pigs and suspended in Tyrode solution of the following composition (in mm): NaCI, 136.8: KCI, 2.7: CaCl2j 2.5; MgC12, 1.0; NaH2PO4j 0.4; NaHCO3, 11.9; and glucose, 5.5. The medium was continuously aerated with 95% 02 and 5 % CO, and maintained at a temperature of 37°C.Tension changes in the smooth muscle preparations were recorded isometrically. Apparatus and procedure in these experiments were the same as those described in previous report (10).In the case of anoxia, 95% 02 of the gas mixture was replaced by 95% N2 gas. The Li-Tyrode solution was prepared by substituting NaCI in Tyrode solution with LiC1 in equivalent millimolarity.K-induced contracture was induced by the addition of 40 mm KCI in Tyrode solu tion without any subtraction of NaCI.

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INCREASE IN 45Ca UPTAKE DURING BARIUM-INDUCED CONTRACTURE IN GUINEA PIG TAENIA COLI

Cited by 3 publications

References 1 publication

Movements of Calcium During Tension Development Induced by Barium and High-Potassium in Guinea Pig Taenia Coli

Movements of Calcium During Tension Development Induced by Barium and High-Potassium in Guinea Pig Taenia Coli

45Ca UPTAKE AND TISSUE Ca OF GUINEA PIG TAENIA COLI IN ISOTONIC HIGH-K/Na-DEFICIENT MEDIUM

Effects of External Calcium and Some Metabolic Inhibitors on Barium-Induced Tension Changes in Guinea Pig Taenia Coli

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