Longer muscle lengths recapitulate force suppression in swine carotid artery.

Cyclic nucleotide can relax arterial smooth muscle without reductions in myosin regulatory light chain (MRLC) phosphorylation, a process termed force suppression. Smooth muscle contractile force also depends on tissue length. It is not known how tissue length affects force suppression.

Increased expression of heat shock protein 20 and decreased contractile stress in obstructed rat bladder.

Purpose: Bladder outlet obstruction induces detrusor hypertrophy and it can eventually lead to decreased bladder smooth muscle contractility. Heat shock protein 20 is the proposed mediator of force suppression in vascular smooth muscle. We investigated whether heat shock protein 20 could also mediate the decreased contractility observed in partially obstructed rat bladders.

Serine 68 phospholemman phosphorylation during forskolin-induced swine carotid artery relaxation.

Background: Phospholemman (PLM) is an abundant phosphoprotein in the plasma membrane of cardiac, skeletal and smooth muscle. It is a member of the FXYD family of proteins that bind to and regulate the Na,K-ATPase. Protein kinase A (PKA) is known to phosphorylate PLM on serine 68 (S68), although the functional effect of S68 PLM phosphorylation is unclear.

Heat shock protein 20-mediated force suppression in forskolin-relaxed swine carotid artery.

Increases in cyclic nucleotide levels induce smooth muscle relaxation by deactivation [reductions in myosin regulatory light chain (MRLC) phosphorylation (e.g., by reduced [Ca(2+)])] or force suppression (reduction in force without reduction in MRLC phosphorylation).