The initiation of receptor-mediated small artery contraction is dependent on inositol 1,4,5-trisphosphate-stimulated release of stored calcium. The role of the other product of inositol lipid hydrolysis, 1,2-diacylglycerol, in maintaining contraction remains controversial. Therefore, we have determined the contractile response of rat subcutaneous small arteries (< 300 microns i.d.), when mounte...

The activities of the soluble and microsomal phosphatidate phosphatases (EC 3.1.3.4) are greater in the livers of essential-fatty-acid-deficient rats than in rats fed diets containing linoleic acid.

The intracellular signalling pathway for alpha-adrenoceptor-mediated negative inotropy was studied pharmacologically in isolated adult mouse ventricle. The negative inotropy was inhibited by GF-109203X, a nonselective protein kinase C inhibitor. Phorbol 12-myristate 13-acetate also produced sustained negative inotropy, which was inhibited by KB-R7943, a Na(+)/Ca(2+) exchanger inhibitor. The alp...

The uptake of [32P]phosphate into phosphatidylinositol and phosphatidate was measured in synaptosomes incubated in Krebs-Ringer bicarbonate buffer, pH7.4. The apparent dissociation constants for acetylcholine and carbamoylcholine was estimated from the increase in 32P uptake caused by these agents. These apparent constants were similar for both phosphatidylinositol and phosphatidate and were 2....

Lysophosphatidate (LPA) stimulates cell migration and division through a family of G-protein-coupled receptors. Lipid phosphate phosphatase-1 (LPP1) regulates the degradation of extracellular LPA as well as the intracellular accumulation of lipid phosphates. Here we show that increasing the catalytic activity of LPP1 decreased the pertussis toxin-sensitive stimulation of fibroblast migration by...

corticosterone production and capsular concentrations of phosphatidic acid, phosphatidyl-inositol, and polyphosphoinositides. These effects are similar to those previously reported for ACTH in the whole adrenal cortex. A common mechanism, i.e., activation of the phosphatidate-polyphosphoinositide cycle, may be operative in the action of steroidogenic agents in their