Voltage-sensitve Ca2+ channels in cardiac left ventricular muscle membranes isolated from nondiabetic control and diabetic rats were measured with [3H]PN 200–110, a dihydropyridine derivative, as a ligand. The binding site (Bmax) of [3H]PN 200–110 in cardiac membranes isolated from streptozocin-induced diabetic (STZ-D) rats (128 ± 10 fmol/mg protein) significantly (P < 0.01) increased by 64% compared with that of control rats (78 ± 4 fmol/mg protein) 10 wk after STZ administration without a significant change in Kd. However, the significant increase in Bmax of [3H]PN 200-110 binding in diabetic rats depended on the duration of diabetes such that the increase was not found until 6 wk after STZ injection. An 8-wk intensive insulin treatment, which was initiated 2 wk after STZ injection, normalized the increase in [3H]PN 200–110 binding in STZ-D rats to control levels (85 ± 4 fmol/mg protein). Furthermore, [3H]PN 200–110 binding to control cardiac membranes was dose-dependently inhibited in the presence of verapamil, a phenylalkylamine Ca2+ antagonist, but that was not the case in cardiac membranes isolated from STZ-D rats. These results indicate that voltage-sensitive Ca2+ channels in cardiac muscle isolated from STZ-D rats are quantitatively and qualitatively altered, because the course of diabetes and the increase in the channels can be prevented by treatment with insulin.
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Original Articles|
September 01 1990
Increase in [3H]PN 200-110 Binding to Cardiac Muscle Membrane in Streptozocin-Induced Diabetic Rats
Yoshihiko Nishio;
Yoshihiko Nishio
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Atsunori Kashiwagi;
Atsunori Kashiwagi
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Tsutomu Ogawa;
Tsutomu Ogawa
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Takayuki Asahina;
Takayuki Asahina
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Motoyoshi Ikebuchi;
Motoyoshi Ikebuchi
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Mitsuaki Kodama;
Mitsuaki Kodama
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Yukio Shigeta
Yukio Shigeta
Department of Medicine, Shiga University of Medical Science
Seta, Ohtsu, Shiga, Japan
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Address correspondence and reprint requests to A. Kashiwagi, MD, Seta, Ohtsu, Shiga 520-21, Japan.
Diabetes 1990;39(9):1064–1069
Article history
Received:
June 09 1989
Revision Received:
April 25 1990
Accepted:
April 25 1990
PubMed:
2143487
Citation
Yoshihiko Nishio, Atsunori Kashiwagi, Tsutomu Ogawa, Takayuki Asahina, Motoyoshi Ikebuchi, Mitsuaki Kodama, Yukio Shigeta; Increase in [3H]PN 200-110 Binding to Cardiac Muscle Membrane in Streptozocin-Induced Diabetic Rats. Diabetes 1 September 1990; 39 (9): 1064–1069. https://doi.org/10.2337/diab.39.9.1064
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