Effect of the Cadmium Ion on the Electrical and Mechanical Activity of the Frog Heart

Kleinfeld, Morris; Greene, Howard; Stein, Edward; Magin, John

doi:10.1152/ajplegacy.1955.181.1.35

Cited by 15 publications

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“…A few investigators (KLEINFELD et al, 1955;TAKAHASHI et al, 1956;KLEINFELD and STEIN, 1968;HAYASHI and HORIUCHI, 1971 a;TODA, 1973) have hitherto described the effects of Cd on the cardiac muscle, but none has tried to study the Cd effect in relation to pH.…”

Section: Discussionmentioning

confidence: 99%

“…This process is considered to be pH-dependent. However, most Cd-uptake into cardiac muscle is pH-independent and may be nonspecific to contraction.Effects of cadmium (Cd) on the electrical and mechanical activities of cardiac muscle in normal pH solution have been studied (KLEINFELD et al, 1955;TAKAHASHI et al, 1956;KLEINFELD and STEIN, 1968;HAYASHI and HORIUCHI, 1971a;TODA, 1973). It was found that a low concentration of Cd (about 10 /AM) brought about a decrease in contractility without an appreciable change in the action potential, and this Cd effect on contractility was completely antagonized by excess Ca (HAYASHI and HORIUCHI, 1971a).…”

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Effects of Cadmium on the Contractility of a Frog Cardiac Muscle in Relation to pH of External Solution

Horiuchi

Hayashi

1979

Jpn.J.Physiol

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In order to examine the pH dependency of Cd effects on cardiac muscle, the electrical and mechanical activities in the bullfrog heart were investigated in relation to various external pHs and concentrations of Cd. The amplitude and duration of the action potential or the spontaneously beating frequency in the atrium were not significantly affected during the 3-min administration of various concentrations of Cd in a range from pH 6 to 10, but the isotonic contraction at the end of the same period was greatly altered: the lower the external pH the more Cd decreased the contractility of the atrium. This pH dependency of Cd effects was also observed in SO4-Ringer's solution whose anions, SO4, were more impermeable than Cl. Decrease in contractility in CdRinger's solution was counteracted by excess Ca. The lower the pH of the Cd-Ringer's solution, the more Ca was necessary to counteract an equal amount of Cd. The amount of Cd-uptake into the atrium was analyzed after soaking the atrium in various concentrations of Cd-Ringer's solution. The higher the concentration of external Cd, the larger the Cd-uptake into the atrium. No pH dependency, however, was observed in this relationship. This suggests that probably only a small fraction of total Cd-uptake interacts with Ca-binding sites which is specific to contraction, and causes the Cd-induced decrease in contractility. This process is considered to be pH-dependent. However, most Cd-uptake into cardiac muscle is pH-independent and may be nonspecific to contraction.Effects of cadmium (Cd) on the electrical and mechanical activities of cardiac muscle in normal pH solution have been studied (KLEINFELD et al., 1955;TAKAHASHI et al., 1956;KLEINFELD and STEIN, 1968;HAYASHI and HORIUCHI, 1971a;TODA, 1973). It was found that a low concentration of Cd (about 10 /AM) brought about a decrease in contractility without an appreciable change in the action potential, and this Cd effect on contractility was completely antagonized by excess Ca (HAYASHI and HORIUCHI, 1971a). It was also reported

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Effects of Cadmium on the Contractility of a Frog Cardiac Muscle in Relation to pH of External Solution

Horiuchi

Hayashi

1979

Jpn.J.Physiol

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“…Unlike skeletal muscle, the myocardium and aorta are sensitive to the inhibitory action of Cd2+ (Kleinfeld et al, 1955;Kleinfeld & Stein, 1968;Thind et al, 1970;Toda, 1973). Also, Cd24 can inhibit Ca24 channels in an axon of Aptysia (Horn, 1978).…”

Section: Discussionmentioning

confidence: 99%

“…In inducing this effect, Cd2" was the most potent among nine divalent cations tested (Fu & Lin-Shiau, 1978;Lin-Shiau & Fu, 1980). In addition, Cd2+ also inhibits the contraction of myocardium and aorta (Kleinfeld et al, 1955;Kleinfeld & Stein, 1968;Thind et al, 1970;Toda, 1973).…”

Section: Introductionmentioning

confidence: 99%

Mode of stimulatory actions of cadmium ion on the mouse diaphragm

Lin‐Shiau

1985

British J Pharmacology

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3 ( + )-Tubocurarine and P-bungarotoxin had no effect on Cd2+-induced spontaneous contractions indicating that they may be myogenic rather than neurogenic in origin. 4 By use of conventional microelectrodes, it was found that Cd2+ not only depolarized the muscle membrane but also induced spontaneous action potentials at a high frequency (173 ± 17 Hz). 5 It is concluded that increased Na+ permeability of the muscle membrane is the essential step bringing about spontaneous contractions. The binding of Cd2+ to -SH groups of the membrane is closely related to the induction of these effects.

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“…In the heart, too, the solution of this problem was pursued by several workers (1,2,3,4,5). The effect of cadmium chloride on the electrical activity of the frog's heart was reported by Logunova and Kipershlak (4), who postulated that the electrocardiographic changes with cadmium chloride was due to a binding of the protein sulfhydryl (SH) groups.…”

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confidence: 99%

Effects of Some Sulfhydryl Reagents on the Mechanical and Electrical Activity of the Toad's Heart

et al. 1956

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Recently, attention of many investigators has been directed to the physiological significance of the protein sulfhydryl (SH) group in various tissues. In the heart, too, the solution of this problem was pursued by several workers (1,2,3,4,5). The effect of cadmium chloride on the electrical activity of the frog's heart was reported by Logunova and Kipershlak (4), who postulated that the electrocardiographic changes with cadmium chloride was due to a binding of the protein sulfhydryl (SH) groups. Afterwards, Kleinfeld et al. (5) revealed the similar disturbance with cadmium chloride in the single myocard fiber, using the microelectrode technique.The following experiments were undertaken, a) to compare the effect of cadmium chloride on the toad's heart with that of mercuric derivatives, such as p-chloromercurobenzoic acid and phenylmercuric acetate which are known to be more specific sulfhydryl reagents, and b) to investigate in details the dissociation of the mechanogram and electrogram of the heart with sulfhydryl reagents. METHODSThe isolated heart of the Japanese toad in winter stage was perfused through Yagi's recurrent perfusion cannula with Ringer solution which contained a test substance of a desired concentration.The cannula was always filled with the fixed volume (5ml.) of perfusates which were adjusted to pH6.8.To transform mechanograms into electrical events, the shadow of a contracting heart, that was exposed to parallel light beams entering through a narrow slit, was projected into a phototube, connected with a three stages amplifier with a time constant of3seconds.Thus, the electrocardiogram and at the same time, the mechanogram were recorded with a ink writing oscillograph, of which natural frequency was70cps.As leading electrodes, the cotton thread/AgC1/Ag type was used.To lead the bipolar electrocardiogram, cotton thread electrodes moistened with Ringer solution were placed on the wall of the auricle and at the apex of the ventricle. For monophasic leading, the indifferent electrode was soaked with isotonic KC1

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Effect of the Cadmium Ion on the Electrical and Mechanical Activity of the Frog Heart

Cited by 15 publications

References 0 publications

Effects of Cadmium on the Contractility of a Frog Cardiac Muscle in Relation to pH of External Solution

Effects of Cadmium on the Contractility of a Frog Cardiac Muscle in Relation to pH of External Solution

Mode of stimulatory actions of cadmium ion on the mouse diaphragm

Effects of Some Sulfhydryl Reagents on the Mechanical and Electrical Activity of the Toad's Heart

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