• Protein kinase C (PKC) is a family of phospholipiddependent Ca 2+ /diacylglycerol-stimulated enzymes. It is an ubiquitous protein that plays a multifunctional role in the transduction of extracellular signals activating the phospholipid turnover and generating diacylglycerol (DAG). DAG can be produced from the hydrolysis of phospatidylinositol-1,4-bisphosphate, phosphatidylcholine, or sphingo...

Radioactive calcium flux in rabbit aorta was studied to evaluate factors regulating the movement of calcium into and out of the cell. Calcium content was estimated both from (1) the amount of Ca present in the tissue and the specific activity of Ca in the bathing medium, and (2) determination of chemical calcium by atomic absorption spectrophotometry. Calcium efflux was followed by washing aort...

Airway smooth muscle contraction is the central event in acute airway narrowing in asthma. Most studies of isolated muscle have focused on statically equilibrated contractile states that arise from isometric or isotonic contractions. It has recently been established, however, that muscle length is determined by a dynamically equilibrated state of the muscle in which small tidal stretches associ...

Cdc42GAP (GTPase activating protein) has been shown to regulate smooth muscle contraction as well as cell motility, adhesion, proliferation, and apoptosis. We have recently shown that Cdc42GAP activity is suppressed in smooth muscle cells during contractile activation, which is reversed by inhibitors of reactive oxygen species (ROS). Because p47(phox), a regulatory subunit of NAD(P)H oxidase, h...

1. Papaverine, in the concentration range 50-150 microM, inhibited rhythmic spontaneous contraction and caused relaxation of KCl-induced contractures of rat ileal smooth muscle. 2. Spontaneous slow waves and spikes declined at low papaverine concentrations. 3. The normal 45Ca uptake of the ileum was reduced by papaverin. Although papaverine caused only a small inhibition of normal 45Ca efflux f...