Manganese on Calcium Flux and Norepinephrine-Induced Tension in Arterial Smooth Muscle

Keene, James J.; Seidel, Charles L.; Bohr, David F.

doi:10.3181/00379727-139-36303

Cited by 16 publications

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“…MnCl2 also possessed multiple actions on the mechanical response of smooth muscle cells of the antrum, namely, this agent suppressed the spontaneous contraction, suppressed the Ca-induced contraction evoked by application of Ca in the Ca-free solution in polarized and depolarized muscles, and prevented the leakage ofCa from the store site, under conditions ofCa-free solution. It was also reported that MnCl2 modifies the Ca influx and penetrates the cell, thus causing either a suppression (Keene, Seidel & Bohr, 1972;Katase & Tomita, 1972;Osa, 1974;Yoshida et al 1977) or an acceleration of the mechanical responses (Shibata, 1969;Ogasawara et al 1980) in various visceral muscles. 573 574 T. ITOH, H. KURIYAMA AND T. NANJO In cells of the antrum, Mn in an extremely low concentration (2 x 10-9 m) may accelerate the interaction of Ca-Ca receptor for contractile protein.…”

Section: Discussionmentioning

confidence: 99%

Effects of calcium and manganese ions on mechanical properties of intact and skinned muscles from the guinea‐pig stomach

Itoh

Kuriyama

Nanjo

1982

The Journal of Physiology

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SUMMARY1. To investigate the mechanism of generation of contractions in tissues from the guinea-pig stomach, the effects of caffeine, procaine, acetylcholine (ACh), diltiazem or MnCl2 on the contraction evoked from small bundles of intact or skinned muscles (50 ,um in width and 250-300 ,um in length) were observed.2. All these agents except for ACh blocked the spontaneously generated contraction. Diltiazem (1 x 10-4 M) had no effect and MnCl2 (3 mM) slightly reduced and caffeine enhanced the tonic contraction evoked in Na-free solution, whereas procaine relaxed the tissue. On the other hand, in the isotonic [K]0 solution, diltiazem, MnCl2 and procaine relaxed the tissue, while caffeine enhanced the tonic contraction.3. Under pre-treatment with Ca-free solution (2 mM-EGTA-containing solution) after depletion of the stored Ca, application of 2-5 mM-Ca and subsequently applied 5 mM-caffeine produced contractions (Ca-and caffeine-induced contractions, respectively). In polarized (5-9 mM-K.) and depolarized (128 mM-KO) muscles, the various agents simultaneously applied with 2-5 mM-Ca modified the amplitude of the Ca-induced and the resulting caffeine-induced contractions. Thus, at least three different Ca influxes required to evoke the Ca-or caffeine-induced contraction were identified; diltiazem-sensitive Ca influx, diltiazem-insensitive but Mn-sensitive Ca influx and Mn-insensitive Ca influx.4. The Ca-and caffeine-induced contractions in Ca-free and 15-5 mM-Na-containing solutions were gradually reduced in amplitude, in proportion to the time of exposure. However, amplitude of the caffeine-induced contractions was inhibited to a greater extent and the duration of the contracts was less prolonged than the case of the Ca-induced contraction.5. In saponin-treated skinned muscles, the minimum concentration of Ca required to produce the contraction was 1 x 10-7 M, and the maximum contraction was evoked by application of 1 x 10-5 M-Ca. The effects ofNa-free solution on the Ca accumulation and release to and from the storage site were also observed in these skinned muscles.

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Section: Discussionmentioning

confidence: 99%

Effects of calcium and manganese ions on mechanical properties of intact and skinned muscles from the guinea‐pig stomach

Itoh

Kuriyama

Nanjo

1982

The Journal of Physiology

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“…In the present experiments, the intracellular cyclic AMP content was more elevated by administration of #6-agonists and relaxin measured in the Mg-free solution, after brief application of 0.6 mm Mg, where the experimental design eliminated the facilitatory effect of Mg on the binding of relaxin to the surface membrane receptors (Mercado-Simmen et al, 1980) Bolton, 1979;Weiss, 1981). Yet its action on contraction is complicated, and is not fully understood; MnCl2 modifies the Ca influx and penetrates the cell, thus causing either a suppression (Keene et al, 1972) or an acceleration (Shibata, 1969;Osa, 1974;Sakai & Uchida, 1981;Itoh et al, 1982;Lategan & Brading, 1988) of the mechanical responses in various visceral muscles. Intracellular accumulation of Mn was experimentally proved to occur in rat ventricular muscle, in which the baseline tension was gradually elevated when exposed to 0.2mm Mn (Chapman & Ellis, 1977).…”

Section: Discussionmentioning

confidence: 99%

Effects of porcine relaxin on contraction, membrane response and cyclic AMP content in rat myometrium in comparison with the effects of isoprenaline and forskolin

Osa

Inoue

Okabe

1991

British J Pharmacology

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1 The longitudinal muscle from the uterus of oestrogen-treated rats was quiescent in Mg-free Krebs solution. Electrical stimulation generated phasic contraction, which was depressed to 35% and 18% by 50 mu and 150 mu porcine relaxin, respectively. 2 The phasic contractions were more strongly depressed to 26% by 50 mu relaxin in solution containing 0.6 mm Mg, and the depression lasted for more than 4 h after the removal of relaxin. During the persisting depression, raising the external Ca to 7.5 mm did not restore the contraction, but the contraction was restored by removal of Mg. 3 The depression of the phasic contraction by relaxin, examined in Mg-free solution, was enhanced and reduced by pretreatment of the tissue with 0.6 mm Mg and 0.6 mm Mn, respectively, for about 15min. In contrast, the depression of contraction by isoprenaline or forskolin was enhanced by pretreatment with either Mg or Mn. 4 The cellular content of cyclic AMP was measured in Krebs solution containing 0.6 mm Mg. The values were 1.24 (pmolmg-' protein) in control solution, and 2.31 and 1.56 when the tissues were treated with 150 mu relaxin and 10-9 M isoprenaline, respectively. 5 The cyclic AMP production in response to 10-7M forskolin measured in Mg-free solution was enhanced when the tissue was pretreated with either 0.6mm Mg or Mn for 15min. The cyclic AMP production in response to 100mu relaxin was increased when the tissue was pretreated with 0.6mm Mg, and was unchanged by pretreatment with Mn. The cyclic AMP production in response to 10-9M isoprenaline was unchanged by pretreatment with the divalent cations. 6 The membrane potential of the muscle was -60.8mV in Krebs solution containing 0.3mm Mg, and electrical stimulation induced an action potential which consisted of spike and plateau components. Application of 150mu relaxin reduced the duration of the plateau; the contractions were progressively depressed. The resting membrane potential and membrane resistance were unchanged by application of 150 mu relaxin. The membrane was hyperpolarized by 2.8 mV, accompanied by a decrease in membrane resistance, when I0-9 M isoprenaline was applied. 7 Although there were several differences between the effects of relaxin and isoprenaline, it is probable that some process, which is cyclic AMP-dependent, accelerated by Mg and depressed by Mn, is involved in the depressant action of relaxin on contraction.

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“…However, the potency of Mn2+ as an antagonist in vivo to pulmonary pressure increases caused by serotonin, histamine or acetylcholine was higher than expected from the data on in vitro preparations, and this antagonism prevented us from being able to demonstrate any action of Mn2+ as a n isoprenaline antagonist in the Konsett-Rossler preparation. This relaxant effect has usually been attributed to the action of manganese as a calcium antagonist (Keene, Seidel & Bohr, 1972;Parnas, Prosser & Rice, 1974;Osa, 1974;Shuba, 1977;Pourrias & Friedrich, 1978;Webb & Bohr. 1978;Rosenberger, Ticku & Triggle, 1979).…”

Section: Discussionmentioning

confidence: 99%

Antagonism by Manganese of Isoprenaline Dilatation of the Guinea‐pig Isolated Trachea

Jamieson¹,

Quinn

Coutier³

1983

Clin Exp Pharma Physio

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Manganese (0.5-100 mumol/l) was found to be a potent inhibitor of the dilator effect of isoprenaline on the isolated tracheal muscle of the guinea-pig. Above these concentrations the inhibitory action of Mn2+ diminished and no inhibition occurred above 1000 mumol/l Mn2+. Thus a bell-shaped dose-response curve resulted for the inhibition of isoprenaline by Mn2+. The antagonism was surmountable but apparently noncompetitive. Dilation of the isolated trachea caused by theophylline or nitroprusside was not inhibited by Mn2+ at concentrations of 12.5 to 750 mumol/l. At the dose range which could be tested manganese did not antagonize isoprenaline bronchodilatation in vivo. However, manganese at doses between 0.5 and 2.0 mumol/kg inhibited increased in pulmonary resistance caused by acetylcholine, histamine or serotonin. At concentrations above 250 mumol/l Mn2+ inhibited constrictor responses to histamine, acetylcholine and serotonin in guinea-pig isolated ileum and trachea, and inhibited serotonin and prostaglandin E2 contractions in rat fundus. Co2+, Fe2+, Fe3+ and Zn2+ were also tested for their action against isoprenaline on the isolated trachea. Co2+ was similar in effect to Mn2+ but had only 1/50 of the potency. Up to the highest concentrations which could be tested, namely 1000 mumol/l, the other trace metals produced negligible effects. Thus Mn2+ showed selective inhibition of the relaxant effect of isoprenaline on the guinea-pig isolated trachea, at concentrations of Mn2+ well below those shown previously to inhibit constrictor responses by block of transmembrane Ca2+ entry. It is suggested that Mn2+ may interfere with intracellular Ca2+ fluxes in the isolated trachea.

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Manganese on Calcium Flux and Norepinephrine-Induced Tension in Arterial Smooth Muscle

Cited by 16 publications

References 1 publication

Effects of calcium and manganese ions on mechanical properties of intact and skinned muscles from the guinea‐pig stomach

Effects of calcium and manganese ions on mechanical properties of intact and skinned muscles from the guinea‐pig stomach

Effects of porcine relaxin on contraction, membrane response and cyclic AMP content in rat myometrium in comparison with the effects of isoprenaline and forskolin

Antagonism by Manganese of Isoprenaline Dilatation of the Guinea‐pig Isolated Trachea

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