Lipoproteins inhibit platelet aggregation and arachidonic acid metabolism in experimental hypercholesterolaemia.

1. Human plasma contains unidentified components that inhibit arachidonic acid (AA) metabolism. In the present study, we investigated whether plasma from rabbits fed a normal or high-cholesterol diet for 16 weeks also inhibits AA metabolism.

Inhibitors of phosphatidylinositide 3-kinase: effects on reactive oxygen species and platelet aggregation.

Phosphoinositide 3-kinase (PI 3-kinase) exists in cells as a family of isoforms. The enzymes are important regulators of fundamental metabolic processes, such as energy utilization, growth, cell proliferation and survival. They are activated by cell surface receptors for hormones, and by G-protein coupled receptors.

Signaling mechanisms mediated by G-protein coupled receptors in human platelets.

Aim: The present study deals with the investigation of mechanisms involved in the synergistic interaction between epinephrine and arachidonic acid (AA).

Methods: Venous blood was taken from healthy human volunteers reported to be free of medications for one week. Platelet aggregation was monitored at 37 degree using Dual-channel Lumi-aggregometer.

Comparison of effects of khat extract and amphetamine on motor behaviors in mice.

The aim of this study was to determine if the psychostimulants, khat and amphetamine, exert similar effects in two tests of motor behaviors. Dose-response relationships were obtained for khat extract and D- and L-amphetamine given to mice by the intragastric route. Head twitch responses were significantly increased by khat and amphetamines.