Post-transcriptional downregulation of sarcolipin mRNA by triiodothyronine in the atrial myocardium.

Thyroid hormone-mediated positive cardiotropic effects are differently regulated between the atria and ventricles. This regulation is, at least in part, dependent on sarcoplasmic reticulum (SR) proteins. Sarcolipin, a homologue of phospholamban, has been recently identified as an atrium-specific SR protein.

Multiple transcripts of Ca2+ channel alpha1-subunits and a novel spliced variant of the alpha1C-subunit in rat ductus arteriosus.

Voltage-dependent Ca(2+) channels (VDCCs), which consist of multiple subtypes, regulate vascular tone in developing arterial smooth muscle, including the ductus arteriosus (DA). First, we examined the expression of VDCC subunits in the Wistar rat DA during development. Among alpha(1)-subunits, alpha(1C) and alpha(1G) were the most predominant isoforms.

Direct inhibition of type 5 adenylyl cyclase prevents myocardial apoptosis without functional deterioration.

Adenylyl cyclase, a major target enzyme of beta-adrenergic receptor signals, is potently and directly inhibited by P-site inhibitors, classic inhibitors of this enzyme, when the enzyme catalytic activity is high. Unlike beta-adrenergic receptor antagonists, this is a non- or uncompetitive inhibition with respect to ATP. We have examined whether we can utilize this enzymatic property to regulate the effects of beta-adrenergic receptor stimulation differentially.