In the past 30 years, only three natural products have been sources of new drugs with antiplatelet activity. In this study, we have demonstrated for the first time that guanosine from Solanum lycopersicum possesses antiplatelet (secretion, spreading, adhesion and aggregation) activity in vitro and inhibition of platelet inflammatory mediator of atherosclerosis (sCD40L). According to ADP-induced...

The rabbit reticulocyte is capable of utilizing purines and their ribosyl derivatives for nucleoside triphosphate formation. Adenine, adenosine, hypoxanthine, and inosine are used extensively for the synthesis of adenosine triphosphate. Xanthine, guanine, and guanosine are utilized primarily for the synthesis of guanosine triphosphate. The inhibitor 6-diazo-S-oxo-L-norleucine inhibits the utili...

Misonidazole, after reduction to the hydroxylamine deriva tive, was found to react with guanosine in aqueous solution at pH 7. The guanosine product was isolated and was assigned a structure having a new 5-membered ring with a —CHOHCHOH-linkage between the N-1 and N-2 positions of guanine. Removal of the sugar residue from the guanosine product by acid hydrolysis resulted in the corresponding...

This study was designed to investigate the protective effects of the combination of guanosine and 2 organoselenium compounds (ebselen and diphenyl diselenide) against glutamate-induced oxidative stress in different regions of rat brains. Glutamate caused an increase in reactive oxygen species (ROS) generation and a decrease in [(3)H]-glutamate uptake in striatal, cortical, and hippocampal slice...

The purpose of this study was to determine whether cyclic guanosine monophosphate inhibits contraction through inhibition of phosphatidylinositol hydrolysis. Sodium nitroprusside and atriopeptin II, agents which activate soluble and particulate guanylate cyclase, respectively, inhibited norepinephrine-induced contraction and accumulation of inositol monophosphate, a measure of phosphatidylinosi...

Guanosine diphosphate mannose first was isolated by Cabib and Leloir (1) from yeast. Since then it has been reported in hen oviduct (a), molds (3, 4), red algae (5), mammary gland (6), and the milk of sheep, goat, and pig (7). The enzyme catalyzing guanosine diphosphate mannose synthesis was reported by Munch-Petersen (8) to occur in yeast, and is known as guanosine diphosphate mannose pyrophos...

While alarmone nucleotides guanosine-3',5'-bisdiphosphate (ppGpp) and guanosine-5'-triphosphate-3'-diphosphate (pppGpp) are archetypical bacterial second messengers, their adenosine analogues ppApp (adenosine-3',5'-bisdiphosphate) pppApp (adenosine-5'-triphosphate-3'-diphosphate) toxic effectors that abrogate growth. The alarmones both synthesized degraded by the members of RelA-SpoT Homologue ...

In cell culture, extracellular guanosine increases extracellular adenosine by attenuating the disposition of extracellular adenosine (American Journal of Physiology - Cell Physiology 304: C406-C421, 2013). The goal of this investigation was to determine whether this "guanosine-adenosine mechanism" is operative in an intact organ. Twenty-seven isolated, perfused mouse kidneys were subjected to m...

BACKGROUND Inhaled nitric oxide produces potent pulmonary vasodilation by activating soluble guanylate cyclase and increasing smooth muscle cell concentrations of cyclic guanosine monophosphate. However, responses are often nonsustained, and clinically significant increases in pulmonary vascular resistance have been noted on its acute withdrawal. In vitro and in vivo data suggest that inhaled n...