[3H]Arachidonic acid is released after stimulation of rabbit neutrophils with fMet-Leu-Phe or platelet-activating factor (PAF). The release is rapid and dose-dependent, and is inhibited in phorbol 12-myristate 13-acetate (PMA)-treated rabbit neutrophils. The protein kinase C (PKC) inhibitor 1-(5-isoquinoline-sulphonyl)-2-methylpiperazine (H-7) prevents this inhibition. In addition, PMA increase...

It is believed that inotropic agents exert their effects in cardiac muscle via a modulation of Ca'+ cycling; however, the involvement of phospholipase activation and the biochemical pathways participating in inotropic responsiveness remain unclear. The aim of the current study was to determine whether arachidonic acid and/or eicosanoids participate in inotropic responses by modulating Ca2' cycl...

Boswellic acids inhibit the transformation of arachidonic acid to leukotrienes via 5-lipoxygenase but can also enhance the liberation of arachidonic acid in human leukocytes and platelets. Using human platelets, we explored the molecular mechanisms underlying the boswellic acid-induced release of arachidonic acid and the subsequent metabolism by platelet-type 12-li-poxygenase (p12-LO). Both bet...

Low concentrations (0.5-1 microM) of cytochalasins inhibit the thrombin-stimulated polymerization of monomeric actin to filamentous actin in platelets. Similar concentrations of cytochalasin B inhibit the formation and metabolism of arachidonic acid in horse platelets stimulated by low concentrations of thrombin (0.1-0.5 unit/ml). However, the release of serotonin is not inhibited by cytochalas...

Porcine aortic endothelial cells were cultured through four passages from primary cultures. The arachidonic acid content of individual phospholipid classes and the release of 6-keto-prostaglandin F1 alpha and 15-hydroxyeicosatetraenoic acid in response to 1 microM ionophore A23187 were assayed at each passage. The content of arachidonic acid in phosphatidylinositol and diacyl phosphatidylethano...

The present study was designed to investigate the effect of dexamethasone treatment for 2 weeks (2.5 mg/kg/week, subcutaneously) on the level of unesterified fatty acids, particularly arachidonic acid, in the renal medulla of rats, and to relate the observed effect to changes in the tissue concentration and the fatty acid composition of renal medulla phospholipids and triglycerides. Dexamethaso...

Arachidonic acid cascade inhibitors, including phospholipase A2 inhibitors, dexamethasone and quinacrine (mepacrine), cyclooxygenase inhibitors, indomethacin and aspirin, and lipoxygenase inhibitor AA861, prevented foam cell formation and cholesterol accumulation in the incubation of thioglycollate-induced mouse peritoneal macrophages with oxidized low density lipoprotein (LDL) at 37 degrees C ...

Bipolar disorder is a major medical, social and economic burden worldwide. However, the biochemical basis of the disorder and the mechanisms of action of effective antibipolar disorder drugs remain elusive. In this paper, we review how combining a kinetic approach to studying the turnover of fatty acids within brain phospholipids of unanesthetized rats along with chronic administration of antim...

The arachidonic acid lipoxygenase products released into culture supernatants by the human myeloid cell line K562 were quantitated by high-performance liquid chromatography. During 2 hr of incubation, K562 cells spontaneously released a mean of 9 ng of 15-monohydroxyeicosatetraenoic acid, 35 ng of 5-monohydroxyeicosatetraenoic acid, and 87 ng of a partially resolved mixture of 11- and 12-monohy...