Palitha Jayasekara

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The nucleotide-sugar-activated P2Y14 receptor (P2Y14-R) is highly expressed in hematopoietic cells. Although the physiologic functions of this receptor remain undefined, it has been strongly implicated recently in immune and inflammatory responses. Lack of availability of receptor-selective high-affinity antagonists has impeded progress in studies of this(More)
Interest is increasing in developing fluorescent ligands for characterization of adenosine receptors (ARs), which hold a promise of usefulness in the drug discovery process. The size of a strategically labeled AR ligand can be greatly increased after the attachment of a fluorophore. The choice of dye moiety (e.g. Alexa Fluor 488), attachment point and(More)
The rumen contents of 63 sika deer (Cervus nippon Temminck) shot in the westernmost part of Honshu were analyzed by the point-frame method. The rumen contents were dominated by forbs and the majority of these were evergreen monocotyledonous plants, probably Ophiopogon spp. Evergreen browse leaves (woody leaves), such as Eurya japonica Thunb., Ilex crenata(More)
We establish structure activity relationships of extracellular nucleosides and nucleotides at G protein-coupled receptors (GPCRs), e.g. adenosine receptors (ARs) and P2Y receptors (P2YRs), respectively. We synthesize selective agents for use as pharmacological probes and potential therapeutic agents (e.g. A3AR agonists for neuropathic pain). Detailed(More)
Extended N(4)-(3-arylpropyl)oxy derivatives of uridine-5'-triphosphate were synthesized and potently stimulated phospholipase C stimulation in astrocytoma cells expressing G protein-coupled human (h) P2Y receptors (P2YRs) activated by UTP (P2Y2/4R) or UDP (P2Y6R). The potent P2Y4R-selective N(4)-(3-phenylpropyl)oxy agonist was phenyl ring-substituted or(More)
5'-AMP-activated protein kinase (AMPK) and its pharmacological modulators have been targeted for treating type 2 diabetes. Extracellular uridine 5'-diphosphate (UDP) activates P2Y6 receptors (P2Y6Rs) in pancreatic β-cells to release insulin and reduce apoptosis, which would benefit diabetes. Here, we studied the role of P2Y6R in activation of AMPK in MIN6(More)
The conventional route to alkoxyamine hydrochloride derivatives is by reaction of alkyl bromides with N-hydroxyphthalimide or N-hydroxysuccinimide followed by addition of hydrazine and HCl. Transformation of an alkyl bromide to the corresponding alkoxyamine hydrochloride can be accomplished more rapidly in high yield and without using hazardous hydrazine by(More)
4-Alkyloxyimino derivatives of pyrimidine nucleotides display high potency as agonists of certain G protein-coupled P2Y receptors (P2YRs). In an effort to functionalize a P2Y6R agonist for fluorescent labeling, we probed two positions (N(4) and γ-phosphate of cytidine derivatives) with various functional groups, including alkynes for click chemistry.(More)
The sambar Cervus unicolor has a large population in southern Asia. In Sri Lanka, its habitat use is most common among the four cervid species. We carried out an analysis of the food habits of sambar in the Horton Plains National Park from January to November 1991 by using the quantitative fecal analysis method. Analyses of sambar feces collected at the(More)
Extracellular nucleotides acting via P2 receptors play important roles in cardiovascular physiology/pathophysiology. Pyrimidine nucleotides activate four G protein-coupled P2Y receptors (P2YRs): P2Y2 and P2Y4 (UTP-activated), P2Y6, and P2Y14. Previously, we showed that uridine 5′-triphosphate (UTP) activating P2Y2R reduced infarct size and improved mouse(More)