scholarly journals Anoxia induces time-independent K+ current through KATP channels in isolated heart cells of the guinea-pig.

1992 ◽  
Vol 454 (1) ◽  
pp. 339-357 ◽  
Author(s):  
K Benndorf ◽  
G Bollmann ◽  
M Friedrich ◽  
H Hirche
Keyword(s):  
Guinea Pig ◽  
Isolated Heart ◽  
Katp Channels ◽  
Heart Cells ◽  
Isolated Heart Cells ◽  
K Current

Role of Cardiac KATP Channels During Anoxia and Ischemia

Physiology ◽  
1997 ◽  
Vol 12 (2) ◽  
pp. 78-83 ◽  
Author(s):  
K Benndorf ◽  
S Thierfelder ◽  
B Doepner ◽  
C Gebhardt ◽  
H Hirche
Keyword(s):  
Time Course ◽  
Isolated Heart ◽  
Katp Channels ◽  
Ischemic Myocardium ◽  
Heart Cells ◽  
Isolated Heart Cells ◽  
Transient Activity

In isolated heart cells, maintained anoxia causes a transient opening of KATP channels. In the ischemic myocardium, this extra K+ conductance results in a decreased contractility and may be arrhythmogenic. Recent studies provide further evidence that the transient activity of KATP channels during anoxia is correlated with the time course of extracellular K+ accumulation during ischemia.

FMRFamide effects on membrane properties of heart cells isolated from the leech, Hirudo medicinalis

1992 ◽  
Vol 67 (2) ◽  
pp. 280-291 ◽  
Author(s):  
K. J. Thompson ◽  
R. L. Calabrese
Keyword(s):  
Isolated Heart ◽  
Muscle Cells ◽  
Membrane Properties ◽  
Slow Inward Current ◽  
Heart Cells ◽  
Linear Component ◽  
Inward Current ◽  
Isolated Heart Cells ◽  
Voltage Dependent ◽  
K Currents

1. The effects of the cardioactive peptide FMRFamide were tested on enzymatically dissociated muscle cells isolated from hearts of the leech. These cells were normally quiescent, with resting potentials near -60 mV. 2. Superfusion of FMRFamide induced a strong depolarization in isolated heart cells (e.g., greater than 40 mV with 10(-6) M FMRFamide). The depolarization was maintained in the continued presence of peptide and persisted long after its removal. Less frequently, FMRFamide superfusion elicited an episodic polarization rhythm. 3. The response of isolated heart cells to bath-applied FMRFamide showed a 1- to 2-min latency. The latency decreased with repeated applications of FMRFamide. 4. The FMRFamide response was diminished by Na+ replacement but persisted with Ca2+ channel blockade. 5. In voltage-clamped heart cells (-60 mv), superfusion of FMRFamide elicited a slow inward current with a transient and a sustained component. 6. Current-voltage (I-V) curves during FMRFamide superfusion in normal leech saline showed that FMRFamide also enhanced voltage-dependent outward currents activated at depolarized levels. 7. Under conditions in which K+ currents were substantially blocked, the FMRFamide-dependent I-V curve was net inward from -90 to +50 mV. A voltage-dependent component was blocked by Co2+ and a linear component by Na+ replacement. 8. We conclude that FMRFamide elicits a persistent inward current with a Na+ component and in addition modulates both voltage-dependent Ca2+ and K+ currents that may contribute to the normal myogenic activity of leech heart muscle cells.

Collagen chain mRNAs in isolated heart cells from young and adult rats*

1988 ◽  
Vol 20 (3) ◽  
pp. 267-276 ◽  
Author(s):  
M EGHBALI ◽  
M CZAJA ◽  
M ZEYDEL ◽  
F WEINER ◽  
M ZERN ◽  
...  
Keyword(s):  
Isolated Heart ◽  
Heart Cells ◽  
Adult Rats ◽  
Isolated Heart Cells ◽  
Collagen Chain

scholarly journals Amino acid uptake in isolated chick embryo heart cells. Effect of insulin

1969 ◽  
Vol 114 (1) ◽  
pp. 97-105 ◽  
Author(s):  
G. G. Guidotti ◽  
Britta Lüneburg ◽  
A. F. Borghetti
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Isolated Heart ◽  
Cardiac Cells ◽  
Cell Permeability ◽  
Heart Cells ◽  
Acid Uptake ◽  
Aminoisobutyric Acid ◽  
Isolated Heart Cells

1. The preparation of cell suspensions by treatment of chick embryo hearts with collagenase at various stages of development is described. 2. Measurements of oxygen consumption, incorporation of labelled leucine into protein and accumulation of labelled α-aminoisobutyric acid against a concentration gradient indicated a long-lasting viability of the isolated heart cells in vitro; a satisfactory preservation of subcellular structures, including plasma membrane, was assessed by electron-microscopic examination. 3. The rate of α-aminoisobutyric acid accumulation by cardiac cells isolated from hearts at different stages of embryological development decreased with aging; insulin stimulated the intracellular accumulation of this amino acid analogue. 4. Insulin increased the uptake by isolated heart cells of several 14C-labelled naturally occurring amino acids; however, the fraction of amino acid taken up by the cells that was recovered free intracellularly, and therefore the concentration ratio (between intracellular water and medium), was enhanced by the hormone only with glycine, proline, serine, threonine, histidine and methionine. When isolated heart cells were incubated in the presence of a mixture of labelled amino acids, the addition of insulin increased the disappearance of radioactivity from the medium. 5. The general pattern of amino acid transport (in the absence and in the presence of insulin) in isolated cardiac cells was similar to that found in intact hearts, suggesting that the biological preparation described in this paper might be useful for studies of cell permeability and insulin action.

Voltage dependence of Na/K pump current in isolated heart cells

Nature ◽  
1985 ◽  
Vol 315 (6014) ◽  
pp. 63-65 ◽  
Author(s):  
David C. Gadsby ◽  
Junko Kimura ◽  
Akinori Noma
Keyword(s):  
Voltage Dependence ◽  
Isolated Heart ◽  
Pump Current ◽  
Heart Cells ◽  
Isolated Heart Cells

Mitochondrial NAD(P)H, ADP, oxidative phosphorylation, and contraction in isolated heart cells

2000 ◽  
Vol 279 (4) ◽  
pp. H1849-H1857 ◽  
Author(s):  
Roy L. White ◽  
Beatrice A. Wittenberg
Keyword(s):  
Contractile Response ◽  
Isolated Heart ◽  
Heart Cells ◽  
Cardiac Work ◽  
Isolated Heart Cells ◽  
Rapid Pacing ◽  
Rat Heart Cells ◽  
Electrical Pacing ◽  
The Relationship ◽  
Physiological Substrates

To examine the relationship between mitochondrial NADH (NADHm) and cardiac work output, NADHm and the amplitude and frequency of the contractile response of electrically paced rat heart cells were measured at 25°C. With 5.4 mM glucose plus 2 mM β-hydroxybutyrate, NADHm was reversibly decreased by 23%, and the amplitude of contraction was reversibly decreased by 27% during 4-Hz pacing. With glucose plus 2 mM pyruvate or with 10 mM 2-deoxy-d-glucose, NADHm was maintained during rapid pacing, and the contractile amplitude remained high. Phosphocreatine levels decreased with 2-deoxy-d-glucose administration but not with rapid pacing. Respiration increased to meet the increased ATP demand at 30°C. The data suggest that 1) when NADHm is decreased during rapid pacing with defined substrates, the amplitude of contraction is decreased; 2) the amplitude of contraction during electrical pacing does not change with rate of pacing when both the ATP and NADHm levels are continuously replenished; and 3) the replenishment of NADHm during pacing with physiological substrates may be rate-limited by substrate supply to mitochondrial dehydrogenases. During activation of mitochondrial dehydrogenases, or a significant increase in free ADP induced by 2-deoxy-d-glucose, this rate limitation is bypassed or overcome.

Intracellular Ca2+ and protein kinase C modulate K+ current in guinea pig heart cells

1987 ◽  
Vol 253 (5) ◽  
pp. H1321-H1324 ◽  
Author(s):  
N. Tohse ◽  
M. Kameyama ◽  
H. Irisawa
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Guinea Pig ◽  
Cell Voltage ◽  
Delayed Rectifier ◽  
Heart Cells ◽  
Guinea Pig Heart ◽  
Kinase C ◽  
Ventricular Cells ◽  
K Current

Effects of protein kinase C (PKC) and intracellular calcium ion (Cai2+) on the delayed rectifier K+ current (IK) were investigated in the single ventricular cells of guinea pig by use of an internal-dialysis method and a whole cell voltage-clamp technique. 12-O-tetradecanoylphorbol-13-acetate (TPA, 10(-9) M), an activator of PKC, increased the amplitude of IK in the presence of Cai2+ higher than 10(-10) M. This effect of TPA was mimicked by a synthetic diacylglycerol, 1-oleoyl-2-acetylglycerol (OAG), 50 micrograms/ml, 125 microM, and was blocked by 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (10 microM). The above findings suggest that IK channels were phosphorylated by PKC and thereby the amplitude of IK was increased. IK was also increased by elevating the concentration of Cai2+ in the absence of TPA. It is thus indicated that IK channels are modulated by Cai2+ not only through activation of PKC but also directly. Our observation may provide a possible mechanism by which Cai2+ mediates the link between the Ca2+ transients during contraction and the action potential duration.

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