In order to examine a possible contribution of cyclic AMP to acetylcholine (ACh) release from guinea pig ileum myenteric plexus, effects of adenylate cyclase inhibitors, phosphodiesterase (PDE) inhibitors and dibutyryl cyclic AMP on the spontaneous and the various stimuli-induced ACh release were investigated. A PDE inhibitor, theophylline (1 mM) increased the ACh release induced by nicotine (6...

The cAMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP), is synthesized from prostaglandin E and activated inositol phosphate. From various tissues only that amount of cyclic PIP can be isolated that constitutes the difference between synthesis and degradation. In order to overcome this drawback, the cyclic PIP degrading enzyme or enzymes had to be characterized prior to search...

....................................................................................................................... x LIST OF ABBREVIATIONS USED ................................................................................ xi ACKNOWLEGMENTS .................................................................................................. xiv CHAPTER 1: INTRODUCTION .........................

Early decision on tumor response after anti-cancer treatment is still an unmet medical need. Here we investigated whether in vivo imaging of apoptosis using linear and cyclic (disulfide-bonded) form of ApoPep-1, a peptide that recognizes histone H1 exposed on apoptotic cells, at an early stage after treatment could predict tumor response to the treatment later. Treatment of stomach tumor cells ...

1. Four 3-alkylxanthines (3-methylxanthine, 3-n-propylxanthine (enprofylline), 3-n-butylxanthine and 3-iso-butylxanthine) and four 1-methyl-3-alkylxanthines (1-methyl-3-methylxanthine (theophylline), 1-methyl-3-n-propylxanthine, 1-methyl-3-n-butylxanthine and 1-methyl-3-iso-butylxanthine (IBMX], were compared in terms of cyclic AMP phosphodiesterase (PDE) inhibition and trachealis muscle relaxa...

The yeast Saccharomyces cerevisiae is shown to be equipped with cyclic GMP, the level of which ranges from 6 pmol/10(9) cells with pressed baker's yeast to 21 pmol/10(9) cells with exponentially growing cells. In extracts from synchronized growing yeast, cyclic GMP increases stepwise, being doubled at the time of each mitosis. Theophylline and 3-isobutyl-1-methylxanthine induce a rapid increase...

A low K,,, guanosine 3’:5’-monophosphate (cyclic GMP)specific phosphodiesterase was purified about 250-fold from crude extracts of the guinea pig lung by steps of DEAEcellulose chromatography, hydroxylapatite treatment, and preparatory polyacrylamide gel electrophoresis. Analytical gel electrophoresis revealed two protein bands, indicating that the enzyme preparation was about 50% homogeneous. ...

OBJECTIVE Glucagon-like peptide-1 (GLP-1) increases intracellular Ca(2+) concentrations ([Ca(2+)](i)), resulting in insulin secretion from pancreatic beta-cells. The molecular mechanism(s) of the GLP-1-mediated regulation of [Ca(2+)](i) was investigated. RESEARCH DESIGN AND METHODS GLP-1-induced changes in [Ca(2+)](i) were measured in beta-cells isolated from Cd38(+/+) and Cd38(-/-) mice. Cal...

The cyclic tetrasaccharide, cyclo-(-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->), was oxidized in high yield to a dicarboxylic acid, cyclo-(-->6)-alpha-D-Glcp-(1-->3)-alpha-D-GlcpA-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-GlcpA-(1-->). The parent and oxidized compound were then screened for the ability to form stable complexes with 20 metal cations. Ion-ex...