We report a structure-based biological approach to identify the proton-transfer pathway in photosystem II. First, molecular dynamics (MD) simulations were conducted analyze H-bond network that may serve as Grotthuss-like proton conduit. MD show D1-Asp61, acceptor of H2O at Mn4CaO5 cluster (W1), forms an via one water molecule with D1-Glu65 but not D2-Glu312. Then, D1-Glu65, D2-Glu312, and adjac...

Long-term inhibition of D2 dopamine receptors using classic D2 dopamine receptor antagonists such as haloperidol often causes a compensatory up-regulation of the D2 dopamine receptors. We investigated whether the long-term inhibition of D2 dopamine receptors using an eukaryotic expression vector housing a cDNA sequence encoding an antisense RNA directed to the D2 dopamine receptor transcript (D...

BACKGROUND Agonist positron emission tomography (PET) tracers for dopamine D2/3 receptors (D2/3Rs) offer greater sensitivity to changes in endogenous dopamine levels than D2/3R antagonist tracers. D2/3R agonist tracers currently available for clinical research are labeled with the short-lived isotope carbon-11, which limits their use. We aimed to develop high-affinity D2R agonists amenable for ...

ATTENUATION OF ANTAGONIST-INDUCED IMPAIRMENT IN DOPAMINE RECEPTOR ONTOGENY BY L-PROLYL-L-LEUCYL-GLYCINAMIDE by Mohamad Iqbal Saleh, M.D. It has been shown by others that the prenatal treatment of rats with haloperidol, a dopamine D2 receptor antagonist, leads to a permanent reduction in the number of striatal dopamine D2 receptors in adulthood. Conversely, postnatal treatment of lactating dams ...

In this report, we investigated whether the D5 dopamine receptor, given its structural and sequence homology with the D1 receptor, could interact with the D2 receptor to mediate a calcium signal similar to the G(q/11) protein-linked phospholipase C-mediated calcium signal resulting from the coactivation of D1 and D2 dopamine receptors within D1-D2 receptor heterooligomers. Fluorescent resonance...

We investigated the mechanism by which T4 regulates its activation to T3 by the type 2 iodothyronine deiodinase (D2). D2 is a short- lived (t1/2 50 min), 31-kDa endoplasmic reticulum (ER) integral membrane selenoenzyme that generates intracellular T3. Inhibition of the ubiquitin (Ub) activating enzyme, E1, or MG132, a proteasome blocker, inhibits both the basal and substrate-induced acceleratio...

Progressive loss of nigrostriatal dopamine (DA) neurons is the neuropathological hallmark of Parkinson's disease (PD). Symptoms of the disease can often be treated by DA D2 agonists and thus seem related to disinhibition of the indirect striatal pathway. However, there is no evidence that symptoms arise by low extracellular DA concentration or are associated with reduced D2 receptor binding. He...

To study the interaction of the nuclear and chloroplast genomes in the biogenesis of the photosynthetic apparatus, nuclear mutants of Chlamydomonas reinhardtii deficient in photosystem II (PSII) activity were analyzed. Two independently-isolated, allelic nuclear mutants show a pleiotropic reduction in a set of functionally related PSII polypeptides. Immunoblot analysis reveals that the two muta...

BACKGROUND Antipsychotics are divided into typical and atypical compounds based on clinical efficacy and side effects. The purpose of this study was to characterize in vitro a series of novel azecine-type compounds at human dopamine D1-D5 and 5HT2A receptors and to assign them to different classes according to their dopamine/5HT2A receptor profile. RESULTS Regardless of using affinity data (p...

METHODS Seven healthy volunteers underwent PET scans with [18F]altanserin and [11C]FLB 457 for 5-HT2A and D2 receptors, respectively. As a measure of receptor density, a binding potential (BP) was calculated from PET data for 76 cerebral cortical regions. A correlation matrix was calculated between the binding potentials of [18F]altanserin and [11C]FLB 457 for those regions. The regional relati...