Apr 1, 1997

Cardiac calcium release channel (ryanodine receptor) in control and cardiomyopathic human hearts: mRNA and protein contents are differentially regulated

Journal of Molecular and Cellular Cardiology
C Sainte BeuveD Charlemagne

Abstract

Abnormal intracellular calcium handling in cardiomyopathic human hearts has been associated with an impaired function of the sarcoplasmic reticulum, but previous reports on the gene expression of the ryanodine receptors (Ry2) are contradictory. We measured the mRNA levels, the protein levels and the number of high affinity [3H]ryanodine binding sites in the left ventricle of non-failing (n = 9) and failing human hearts [idiopathic dilated (IDCM n = 16), ischemic (ICM n = 7) or mixed (MCM n = 8) cardiomyopathies]. Ry2 mRNA levels were significantly reduced in IDCM (-30%) and unchanged in MCM and ICM and Ry2 protein levels were similar. In contrast, we observed a two-fold increase in the number of high affinity Ry2 (B(max) = 0.43 +/- 0.11 v 0.22 +/- 0.13 pmol/mg protein, respectively; P<0.01) and an unchanged K(d). Furthermore, levels of myosin heavy chain mRNA and protein per g of tissue were similar in failing and non-failing hearts, suggesting that the observed differences in Ry2 are not caused by the increase in fibrosis in failing heart. Therefore, the dissociation between the two-fold increase in the number of high affinity ryanodine receptors observed in all failing hearts and the slightly decreased mRNA level or unchanged...Continue Reading

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Mentioned in this Paper

Cardiomyopathy, Familial Idiopathic
Failed Back Surgery Syndrome
Channel Activity
Calcium [EPC]
Mycobacterium Avium-intracellulare Infection
Ryanodine Receptor 3
Calcium
Left Ventricular Structure
Protoplasm
Myocardium

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