TY - JOUR
T1 - Effects of acidosis on ventricular myocyte shortening and intracellular Ca2+ in streptozotocin-induced diabetic rats
AU - Howarth, Frank Christopher
AU - Qureshi, Anwar
AU - Singh, Jaipaul
N1 - Funding Information:
This research was supported by a grant from the Faculty of Medicine & Health Sciences, United Arab Emirates University.
PY - 2004/6
Y1 - 2004/6
N2 - We have investigated the effects of acute acidosis on ventricular myocyte shortening and intracellular Ca2+ in streptozotocin (STZ)-induced diabetic rat. Shortening and intracellular Ca2+ were measured in electrically stimulated myocytes superfused with either normal Tyrode solution pH adjusted to either 7.4 (control solution) or 6.4 (acid solution). Experiments were performed at 35-36°C. At 8-12 weeks after treatment, the rats that received STZ had lower body and heart weights compared to controls, and blood glucose was characteristically increased. Contractile defects in myocytes from diabetic rat were characterized by prolonged time to peak shortening. Superfusion of myocytes from control and diabetic rats with acid solution caused a significant reduction in the amplitude of shortening; however, the magnitude of the response was not altered by STZ treatment. Acid solution also caused significant and quantitatively similar reductions in the amplitude of Ca2+ transients in myocytes from control and diabetic rats. Effects of acute acidosis on amplitude of myocyte contraction and Ca2+ transient were not significantly altered by STZ treatment. Altered myofilament sensitivity to Ca2+ and altered mechanisms of sarcoplasmic reticulum Ca2+ transport might partly underlie the acidosis-evoked reduction in amplitude of shortening in myocytes from control and STZ-induced diabetic rat.
AB - We have investigated the effects of acute acidosis on ventricular myocyte shortening and intracellular Ca2+ in streptozotocin (STZ)-induced diabetic rat. Shortening and intracellular Ca2+ were measured in electrically stimulated myocytes superfused with either normal Tyrode solution pH adjusted to either 7.4 (control solution) or 6.4 (acid solution). Experiments were performed at 35-36°C. At 8-12 weeks after treatment, the rats that received STZ had lower body and heart weights compared to controls, and blood glucose was characteristically increased. Contractile defects in myocytes from diabetic rat were characterized by prolonged time to peak shortening. Superfusion of myocytes from control and diabetic rats with acid solution caused a significant reduction in the amplitude of shortening; however, the magnitude of the response was not altered by STZ treatment. Acid solution also caused significant and quantitatively similar reductions in the amplitude of Ca2+ transients in myocytes from control and diabetic rats. Effects of acute acidosis on amplitude of myocyte contraction and Ca2+ transient were not significantly altered by STZ treatment. Altered myofilament sensitivity to Ca2+ and altered mechanisms of sarcoplasmic reticulum Ca2+ transport might partly underlie the acidosis-evoked reduction in amplitude of shortening in myocytes from control and STZ-induced diabetic rat.
KW - Calcium
KW - Contraction
KW - Diabetes
KW - Heart
KW - Streptozotocin
KW - Ventricular myocytes
KW - pH
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U2 - 10.1023/B:MCBI.0000028760.81889.98
DO - 10.1023/B:MCBI.0000028760.81889.98
M3 - Article
C2 - 15362508
AN - SCOPUS:3442901935
SN - 0300-8177
VL - 261
SP - 227
EP - 233
JO - Molecular and cellular biochemistry
JF - Molecular and cellular biochemistry
IS - 1
ER -