Bumetanide prevents diazepam-modified anxiety-like behavior in lipopolysaccharide-treated mice.

Benzodiazepine receptor agonists are widely prescribed therapeutic agents that alter gamma-aminobutyric acid (GABA)A receptor activity and have anxiolytic effects. Post-operative use of benzodiazepines is a risk factor of delirium. Inflammatory conditions alter the anxiolytic effects of benzodiazepine. We investigated the effect of diazepam, a typical benzodiazepine anxiolytic, on changes in the emotional behavior of mice in a hole-board test after lipopolysaccharide (LPS) treatment. Diazepam dose-dependently increased the number of head-dips at doses that did not alter locomotor activity; however, diazepam dose-dependently significantly decreased the number of head-dips at doses that did not alter locomotor activity in LPS-treated mice. Flumazenil, a benzodiazepine receptor antagonist, normalized the decrease in head-dipping behavior caused by diazepam treatment in normal and LPS-treated mice. The decrease of the head-dipping effect caused by diazepam was attenuated by minocycline in LPS-treated mice. We further found that the decrease in head-dipping behavior caused by diazepam was blocked by bumetanide, a Na+-K+-2Cl- cotransporter isoform 1 (NKCC1) antagonist, in LPS-treated mice. These findings suggest that diazepam induces the anxiety-like behavior under inflammation conditions, and may cause the GABAA receptor dysfunction associated with the chloride plasticity mediated by NKCC1, which contributes to benzodiazepine-induced delirium after surgery.

Electronic structure of delocalized singlet biradical Ph2-IDPL solid film.

The film structure and electronic structure of a biradical hydrocarbon, diphenyl derivative of s-indacenodiphenalene (Ph(2)-IDPL) solid film has been investigated. A small energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) compared with that of typical π-conjugated small molecules was observed even for the amorphous film of Ph(2)-IDPL. This result indicates that the small HOMO-LUMO gap is an important characteristic of the singlet biradical electronic structure and well explains the previously reported ambipolar field effects of amorphous Ph(2)-IDPL film by Chikamatsu et al., Appl. Phys. Lett. 2007, 91, 043506. It was found that the gas-deposition method substantially improved the crystallinity of the film where Ph(2)-IDPL molecules form quasi one-dimensional (1D) molecular chains normal to the substrate surface. An extremely small HOMO-LUMO gap was observed in the polycrystalline Ph(2)-IDPL film, which is possibly caused by strong intermolecular coupling. The photon energy dependence of ultraviolet photoemission spectra shows that the stacked Ph(2)-IDPL molecular chain in the polycrystalline film develops an energy band structure in the direction of the surface normal of the film. The intermolecular covalency therefore evolves into the quasi 1D energy band along the molecular stacking direction.

Electronic structure of disjoint diradical 4,4'-bis(1,2,3,5-dithiadiazolyl) thin films.

The electronic structure of the thiazyl diradical, 4,4'-bis(1,2,3,5-dithiadiazolyl) (BDTDA), has been investigated by ultraviolet photoemission spectroscopy. Stacked BDTDA dimers showed an energy band dispersion of about 0.3 eV for the highest occupied molecular orbital in the direction of the surface normal of the BDTDA solid film. The pi-orbital overlap between the stacked dimers therefore evolves into a quasi one-dimensional energy band along the dimer stacking direction.

Interactive radical dimers in photoconductive organic thin films.

Fully interactive: Overlap between extended unoccupied molecular orbitals leads to the high photoconductivity of interactive radical dimers. Sandwich-type cells (see picture; ITO = indium tin oxide) comprising highly oriented thin films of a disjoint diradical, 4,4'-bis(1,2,3,5-dithiadiazolyl) (BDTDA) exhibit a photocurrent with a high on/off ratio at reverse bias voltages and photovoltaic behavior at zero bias voltage.

Calcineurin-inhibitor-induced pain syndrome after bone marrow transplantation.

Calcineurin-inhibitor-induced pain syndrome (CIPS), a rare complication seen in patients with organ transplants, is associated with the use of calcineurin inhibitors (CIs) such as cyclosporine (CSP) and tacrolimus (FK). Patients with this syndrome usually present with severe leg pain. This case report demonstrates the successful pain control of this pain syndrome in a 42-year-old female patient who had been given CIs (FK and CSP) as an immunosuppressive agent after a bone marrow transplant. Twenty-one days after the transplantation, she complained of severe pain in her bilateral lower extremities; this lasted several weeks, and was resistant to ordinary analgesics such as intramuscular pentazocine, intravenous morphine, and even oral nifedipine, which is generally accepted as an effective analgesic agent for the pain in this syndrome. Due to the presence of allodynia, our patient's pain had neuropathic pain-like characteristics, unlike the pain in previously reported patients with other organ transplants. Her pain was successfully relieved by the administration of oral amytriptyline, clonazepam, oxycodone, and intravenous lidocaine, all of which ordinarily have an analgesic effect on neuropathic pain. CIPS in patients with hematopoietic stem cell transplants treated with FK may have a mechanism by which neuropathic pain may develop that is different from that in patients with other organ transplants.

Superoxide production at phagosomal cup/phagosome through beta I protein kinase C during Fc gamma R-mediated phagocytosis in microglia.

Protein kinase C (PKC) plays a prominent role in immune signaling. To elucidate the signal transduction in a respiratory burst and isoform-specific function of PKC during FcgammaR-mediated phagocytosis, we used live, digital fluorescence imaging of mouse microglial cells expressing GFP-tagged molecules. betaI PKC, epsilonPKC, and diacylglycerol kinase (DGK) beta dynamically and transiently accumulated around IgG-opsonized beads (BIgG). Moreover, the accumulation of p47(phox), an essential cytosolic component of NADPH oxidase and a substrate for betaI PKC, at the phagosomal cup/phagosome was apparent during BIgG ingestion. Superoxide (O(2)(-)) production was profoundly inhibited by Gö6976, a cPKC inhibitor, and dramatically increased by the DGK inhibitor, R59949. Ultrastructural analysis revealed that BIgG induced O(2)(-) production at the phagosome but not at the intracellular granules. We conclude that activation/accumulation of betaI PKC is involved in O(2)(-) production, and that O(2)(-) production is primarily initiated at the phagosomal cup/phagosome. This study also suggests that DGKbeta plays a prominent role in regulation of O(2)(-) production during FcgammaR-mediated phagocytosis.

Solution structure of atypical protein kinase C PB1 domain and its mode of interaction with ZIP/p62 and MEK5.

Atypical protein kinase C (aPKC) has been implicated in several signaling pathways such as cell polarity, cell survival, and cell differentiation. In contrast to other PKCs, aPKC is unique in having the PB1 (Phox and Bem 1) domain in the N terminus. The aPKC PB1 domain binds with ZIP/p62, Par6, or MEK5 through a PB1-PB1 domain interaction that controls the localization of aPKC. Here, we determined the three-dimensional structure of the PB1 domain of PKCiota by NMR and found that the PB1 domain adopts a ubiquitin fold. The OPCA (OPR, PC, and AID) motif inserted into the ubiquitin fold was presented as a betabetaalpha fold in which the side chains of conserved Asp residues were oriented to the same direction to form an acidic surface. This structural feature suggested that the acidic surface of the PKCiota PB1 domain interacted with the basic surface of the target PB1 domains, and this was confirmed in the case of the PKCiota-ZIP/p62 complex by mutational analysis. Interestingly, in the PKCiota PB1 domain a conserved lysine residue was located on the side opposite to the OPCA motif-presenting surface, suggesting dual roles for the PKCiota PB1 domain in that it could interact with either the conserved lysine residue or the acidic residues on the OPCA motif of the target PB1 domains.

Molecular recognition in dimerization between PB1 domains.

The PB1 (Phox and Bem 1) domain is a recently identified module that mediates formation of a heterodimeric complex with other PB1 domain, e.g. the complexes between the phagocyte oxidase activators p67phox and p40phox and between the yeast polarity proteins Bem1p and Cdc24p. These PB1 domains harbor either a conserved lysine residue on one side or an acidic OPCA (OPR/PC/AID) motif around the other side; the lysine of p67phox or Bem1p likely binds to the OPCA of p40phox or Cdc24p, respectively, via electrostatic interactions. To further understand molecular recognition by PB1 domains, here we investigate the interactions mediated by proteins presenting both the lysine and OPCA on a single PB1 domain, namely Par6, atypical protein kinase C (aPKC), and ZIP. Par6 and aPKC form a complex via the interaction of the Par6 lysine with aPKC-OPCA but not via that between the aPKC lysine and Par6-OPCA, thereby localizing to the tight junction of epithelial cells. aPKC also uses its OPCA to interact with ZIP, another protein that has a PB1 domain presenting both the lysine and OPCA, whereas aPKC binds via the conserved lysine to MEK5 in the same manner as ZIP interacts with MEK5. In addition, ZIP can form a homotypic complex via the conserved electrostatic interactions. Thus the PB1 domain appears to be a protein module that fully exploits its two mutually interacting elements in molecular recognition to expand its repertoire of protein-protein interactions.

PAR3beta, a novel homologue of the cell polarity protein PAR3, localizes to tight junctions.

The cell polarity protein PAR3, conserved from the nematode to the vertebrate, forms a complex with PAR6 and atypical protein kinase C (aPKC), and the protein complex occurs at the tight junctions in mammalian epithelial cells. Here we have cloned human cDNA for a novel PAR3 homologue, designated PAR3beta, whose messages are present in a variety of tissues and most abundantly expressed in the adult and fetal kidneys. The encoded protein of 1,205 amino acids contains a region homologous to the aPKC-binding domain of PAR3alpha, another human homologue previously identified, and three PDZ domains; the first PDZ domain of PAR3alpha is considered to interact with PAR6. Unexpectedly, in contrast to other PAR3s found in various species, PAR3beta is incapable of binding to any isotypes of PAR6 or aPKC. Nevertheless PAR3beta, expressed intrinsically or extrinsically, localizes to the tight junctions, indicating that the localization does not require the ternary complex formation.