Pyruvate potentiates inotropic effects of isoproterenol and Ca(2+) in rabbit cardiac muscle preparations.
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Pyruvate potentiates inotropic effects of isoproterenol and Ca(2+) in rabbit cardiac muscle preparations. / Hermann, H P; Zeitz, Oliver; Keweloh, B; Hasenfuss, G; Janssen, P M.
In: AM J PHYSIOL-HEART C, Vol. 279, No. 2, 2, 2000, p. 702-708.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Pyruvate potentiates inotropic effects of isoproterenol and Ca(2+) in rabbit cardiac muscle preparations.
AU - Hermann, H P
AU - Zeitz, Oliver
AU - Keweloh, B
AU - Hasenfuss, G
AU - Janssen, P M
PY - 2000
Y1 - 2000
N2 - Catecholamines and elevated extracellular Ca(2+) concentration ([Ca(2+)](o)) augment contractile force by increased Ca(2+) influx and subsequent increased sarcoplasmic reticulum (SR) Ca(2+) release. We tested the hypothesis that pyruvate potentiates Ca(2+) release and inotropic response to isoproterenol and elevated [Ca(2+)](o), since this might be of potential importance in a clinical setting to circumvent deleterious effects on energy demand during application of catecholamines. Therefore, we investigated isometrically contracting myocardial preparations from rabbit hearts at 37 degrees C, pH 7.4, and a stimulation frequency of 1 Hz. At a [Ca(2+)](o) of 1.25 mM, pyruvate (10 mM) alone increased developed force (F(dev)) from 1.89 +/- 0.42 to 3.62 +/- 0.62 (SE) mN/mm(2) (n = 8, P <0.05) and isoproterenol (10(-6) M) alone increased F(dev) from 2.06 +/- 0. 55 to 25.11 +/- 2.1 mN/mm(2) (P <0.05), whereas the combination of isoproterenol and pyruvate increased F(dev) overproportionally from 1.89 +/- 0.42 to 33.31 +/- 3.18 mN/mm(2) (P <0.05). In a separate series of experiments, we assessed SR Ca(2+) content by means of rapid cooling contractures and observed that, despite no further increase in F(dev) by increasing [Ca(2+)](o) from 8 to 16 mM, 10 mM pyruvate could still increase F(dev) from 26.4 +/- 6.8 to 29.7 +/- 7. 1 mN/mm(2) (P <0.05, n = 9) as well as the Ca(2+) load of the SR. The results show that the positive inotropic effects of pyruvate potentiate the inotropic effects of isoproterenol or Ca(2+), because in the presence of pyruvate, Ca(2+) and isoproterenol induced larger increases in inotropy than can be calculated by mere addition of the individual effects.
AB - Catecholamines and elevated extracellular Ca(2+) concentration ([Ca(2+)](o)) augment contractile force by increased Ca(2+) influx and subsequent increased sarcoplasmic reticulum (SR) Ca(2+) release. We tested the hypothesis that pyruvate potentiates Ca(2+) release and inotropic response to isoproterenol and elevated [Ca(2+)](o), since this might be of potential importance in a clinical setting to circumvent deleterious effects on energy demand during application of catecholamines. Therefore, we investigated isometrically contracting myocardial preparations from rabbit hearts at 37 degrees C, pH 7.4, and a stimulation frequency of 1 Hz. At a [Ca(2+)](o) of 1.25 mM, pyruvate (10 mM) alone increased developed force (F(dev)) from 1.89 +/- 0.42 to 3.62 +/- 0.62 (SE) mN/mm(2) (n = 8, P <0.05) and isoproterenol (10(-6) M) alone increased F(dev) from 2.06 +/- 0. 55 to 25.11 +/- 2.1 mN/mm(2) (P <0.05), whereas the combination of isoproterenol and pyruvate increased F(dev) overproportionally from 1.89 +/- 0.42 to 33.31 +/- 3.18 mN/mm(2) (P <0.05). In a separate series of experiments, we assessed SR Ca(2+) content by means of rapid cooling contractures and observed that, despite no further increase in F(dev) by increasing [Ca(2+)](o) from 8 to 16 mM, 10 mM pyruvate could still increase F(dev) from 26.4 +/- 6.8 to 29.7 +/- 7. 1 mN/mm(2) (P <0.05, n = 9) as well as the Ca(2+) load of the SR. The results show that the positive inotropic effects of pyruvate potentiate the inotropic effects of isoproterenol or Ca(2+), because in the presence of pyruvate, Ca(2+) and isoproterenol induced larger increases in inotropy than can be calculated by mere addition of the individual effects.
M3 - SCORING: Zeitschriftenaufsatz
VL - 279
SP - 702
EP - 708
JO - AM J PHYSIOL-HEART C
JF - AM J PHYSIOL-HEART C
SN - 0363-6135
IS - 2
M1 - 2
ER -