|
|
||||||||
Department of Life Science, Kwangju Institute of Science and Technology, Kwangju 500-712, Korea
Chronic treatment
with cyclosporin A (CsA) has been reported (H. S. Banijamali, M. H. ter
Keurs, L. C. Paul, and H. E. ter Keurs.
Cardiovasc. Res. 27: 1845-1854,
1993; I. Kingma, E. Harmsen, H. E. ter Keurs, H. Benediktsson, and L. C. Paul. Int. J. Cardiol. 31:
15-22, 1991) to induce reversible alterations of contractile properties in rat hearts. To define the molecular mechanisms underlying the physiological alterations, the
Ca2+-release channel (CRC) and
Ca2+-ATPase from sarcoplasmic
reticulum in rats were examined. Ryanodine binding to whole homogenates
of rat hearts shows time- and dose-dependent alterations in CRC
properties by CsA. On 3 wk of treatment with 15 mg
CsA · kg body
wt
1 · day
1,
1) maximal ryanodine binding
(Bmax) decreased,
2) the dissociation constant of
ryanodine (Kd)
increased, 3) caffeine sensitivity of CRC increased, and 4) ruthenium
red sensitivity of CRC decreased. On the other hand,
Bmax and
Kd of ryanodine
binding in rat skeletal muscles were not changed. Ryanodine-sensitive
oxalate-supported Ca2+ uptake in
whole homogenates was lower in CsA-treated rat hearts than in control
hearts, whereas total Ca2+ uptake
in the presence of 500 M ryanodine was not changed. Functional experiments with rapamycin and Western blot analysis suggest that the
CsA-induced alteration of ryanodine binding is due at least in part to
an upregulation of calcineurin. The heart muscle-specific alterations
of CRC could be responsible for the previously reported contractile
changes of CsA-treated rat hearts.
immunosuppressant; excitation-contraction coupling; ryanodine receptor; cardiotoxicity; caffeine
This article has been cited by other articles:
![]() |
M. J. McKenna, S. F. Fraser, J. L. Li, X. N. Wang, M. F. Carey, E. A. Side, J. Morton, G. I. Snell, K. Kjeldsen, and T. J. Williams Impaired muscle Ca2+ and K+ regulation contribute to poor exercise performance post-lung transplantation J Appl Physiol, October 1, 2003; 95(4): 1606 - 1616. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Wang, B. Nolan, W. Kutschke, and J. A. Hill Na+-Ca2+ Exchanger Remodeling in Pressure Overload Cardiac Hypertrophy J. Biol. Chem., May 18, 2001; 276(21): 17706 - 17711. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |