TY - GEN
T1 - Effect of streptozotocin-induced type 1 diabetes mellitus on contraction, calcium transient, and cation contents in the isolated rat heart
AU - Singh, Jaipaul
AU - Chonkar, Apurva
AU - Bracken, Nicholas
AU - Adeghate, Ernest
AU - Latt, Zay
AU - Hussain, Munir
PY - 2006/11
Y1 - 2006/11
N2 - Cations play major physiological and biochemical roles in the excitation-contraction coupling processes in the heart. This study investigated the effect of streptozotocin (STZ)-induced type I diabetes mellitus (DM) on contraction, calcium transient [Ca2+]i, and cation contents in the isolated rat heart compared to age-matched control. Diabetes rats weighed significantly (P < 0.05) less compared to control. They also had significantly (P < 0.05) elevated blood glucose compared to control. The whole heart, as well as the atria, right and left ventricles of the diabetic heart weighed significantly (P < 0.05) less compared to hearts from age control rats. The force of contraction and time to peak (t-pk) contraction in diabetic ventricular myocytes increased significantly (P < 0.05) compared to control. By contrast, these parameters did not change for the Ca2+ transient except for the time to half (t 1/2) relaxation. The levels of sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), copper (Cu2+), and zinc (Zn2+) in the hearts varied from diabetic compared to control animals. The results indicate that 6-8 weeks of STZ-induced DM is associated with marked changes in contraction and in cation contents of the heart. The delay in the t 1/2 relaxation of the Ca2+ transient may be responsible for the elevated contraction seen in the diabetic heart. Moreover, the changes in cation contents in the heart may be responsible for abnormal cardiac rhythms and activity during DM.
AB - Cations play major physiological and biochemical roles in the excitation-contraction coupling processes in the heart. This study investigated the effect of streptozotocin (STZ)-induced type I diabetes mellitus (DM) on contraction, calcium transient [Ca2+]i, and cation contents in the isolated rat heart compared to age-matched control. Diabetes rats weighed significantly (P < 0.05) less compared to control. They also had significantly (P < 0.05) elevated blood glucose compared to control. The whole heart, as well as the atria, right and left ventricles of the diabetic heart weighed significantly (P < 0.05) less compared to hearts from age control rats. The force of contraction and time to peak (t-pk) contraction in diabetic ventricular myocytes increased significantly (P < 0.05) compared to control. By contrast, these parameters did not change for the Ca2+ transient except for the time to half (t 1/2) relaxation. The levels of sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), copper (Cu2+), and zinc (Zn2+) in the hearts varied from diabetic compared to control animals. The results indicate that 6-8 weeks of STZ-induced DM is associated with marked changes in contraction and in cation contents of the heart. The delay in the t 1/2 relaxation of the Ca2+ transient may be responsible for the elevated contraction seen in the diabetic heart. Moreover, the changes in cation contents in the heart may be responsible for abnormal cardiac rhythms and activity during DM.
KW - Calcium
KW - Cations
KW - Contraction
KW - Diabetes mellitus
KW - Heart
KW - Rat
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U2 - 10.1196/annals.1372.028
DO - 10.1196/annals.1372.028
M3 - Conference contribution
C2 - 17151301
AN - SCOPUS:34447633184
SN - 1573316350
SN - 9781573316354
T3 - Annals of the New York Academy of Sciences
SP - 178
EP - 190
BT - Diabetes Mellitus and Its Complications
PB - Blackwell Publishing Inc.
ER -