74 research outputs found
Regulation of myocardial Ca2+-ATPase and phospholamban mRNA expression in response to pressure overload and thyroid hormone.
Effects of cyclopiazonic acid and dexamethasone on serotonin-induced calcium responses in vascular smooth muscle cells
Thyroid hormone-induced overexpression of functional ryanodine receptors in the rabbit heart
Regulation of sarcoplasmic reticulum gene expression during cardiac and skeletal muscle development
Age-related changes in sarcoplasmic reticulum Ca(2+)-ATPase and alpha-smooth muscle actin gene expression in aortas of normotensive and spontaneously hypertensive rats.
Exogenous Ca2+-ATPase isoform effects on Ca2+ transients of embryonic chicken and neonatal rat cardiac myocytes
Sarco-endoplasmic reticulum Ca2+-ATPase from fast skeletal (SERCA1) or cardiac muscle (SERCA2a) was expressed in embryonic chicken and neonatal rat cardiac myocytes by adenovirus vectors, with c-myc tags on both constructs to compare expression and distinguish exogenous from endogenous SERCA2a in myocytes.Expression of the two isoforms was similar (approximately 3-fold higher than endogenous SERCA). However, SERCA1 activity was 2-fold greater than SERCA2a activity, due to intrinsic differences in turnover rates. Activation of both exogenous SERCA isoforms by Ca2+ was displaced to slightly lower [Ca2+], suggesting that the overexpressed isoforms were independent of phospholamban. In fact, phospholamban and calsequestrin expression were unchanged.Decay time constants of cytosolic Ca2+ transients from cells overexpressing SERCA1 were reduced by 30ā40 % and half-widths by 10ā15 % compared to controls. SERCA2a overexpression produced much less acceleration of transients in chick than in rat, and less acceleration than SERCA1 overexpression in either species. There was no significant change in resting [Ca2+], peak amplitudes, or in the amount of Ca2+ releasable by caffeine from overexpression of either SERCA isoform. However, the amplitudes of the transients increased with SERCA1 overexpression when pacing frequency limited refilling of the sarcoplasmic reticulum.It is concluded that total SERCA transport velocity has a primary effect on the decay phase of transients. Transport velocity is affected by SERCA isoform turnover rate, temperature, and/or SERCA copy number
Histidine-rich calcium binding protein: The new regulator of sarcoplasmic reticulum calcium cycling
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