Are Future Doctors Taught to Respond to Intimate Partner Violence? A Study of Australian Medical Schools.

Intimate partner violence (IPV) is a leading cause of morbidity and mortality among women of childbearing age. This study aimed to describe delivery of IPV education in Australian pre-vocational medical degrees, and barriers and facilitators influencing this delivery. Eighteen Australian medical schools offering pre-vocational medical degrees were identified. Two were excluded as they had not finalized new curricula. One declined to participate. At least one staff member from each of the remaining 15 schools completed a telephone survey. Main outcome measures included whether IPV education was delivered within the degree, at what stage, and whether it was compulsory; mode and number of hours of delivery; and barriers and facilitators to delivery. Twelve of the medical schools delivered IPV education (median time spent per course = 2 hr). IPV content was typically included as part of Obstetrics and Gynecology or General Practice curriculum. Barriers included time constraints and lack of faculty commitment, resources, and funding. The two schools that successfully implemented a comprehensive IPV curriculum used an integrated, advocacy-based approach, with careful forward planning. Most Australian pre-vocational medical students receive little or no IPV education. The need remains for a more consistent, comprehensive approach to IPV education in medical degrees.

Protective role of reactive astrocytes in brain ischemia.

Reactive astrocytes are thought to protect the penumbra during brain ischemia, but direct evidence has been lacking due to the absence of suitable experimental models. Previously, we generated mice deficient in two intermediate filament (IF) proteins, glial fibrillary acidic protein (GFAP) and vimentin, whose upregulation is the hallmark of reactive astrocytes. GFAP(-/-)Vim(-/-) mice exhibit attenuated posttraumatic reactive gliosis, improved integration of neural grafts, and posttraumatic regeneration. Seven days after middle cerebral artery (MCA) transection, infarct volume was 210 to 350% higher in GFAP(-/-)Vim(-/-) than in wild-type (WT) mice; GFAP(-/-), Vim(-/-) and WT mice had the same infarct volume. Endothelin B receptor (ET(B)R) immunoreactivity was strong on cultured astrocytes and reactive astrocytes around infarct in WT mice but undetectable in GFAP(-/-)Vim(-/-) astrocytes. In WT astrocytes, ET(B)R colocalized extensively with bundles of IFs. GFAP(-/-)Vim(-/-) astrocytes showed attenuated endothelin-3-induced blockage of gap junctions. Total and glutamate transporter-1 (GLT-1)-mediated glutamate transport was lower in GFAP(-/-)Vim(-/-) than in WT mice. DNA array analysis and quantitative real-time PCR showed downregulation of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of tissue plasminogen activator. Thus, reactive astrocytes have a protective role in brain ischemia, and the absence of astrocyte IFs is linked to changes in glutamate transport, ET(B)R-mediated control of gap junctions, and PAI-1 expression.

Binding and transport of [3H](2S,4R)- 4-methylglutamate, a new ligand for glutamate transporters, demonstrate labeling of EAAT1 in cultured murine astrocytes.

Transporters for L-glutamate (excitatory amino acid transporters; EAATs), localized to astrocytes, are involved intimately in intermediary metabolism within the brain. Because (2S,4R)-4-methylglutamate (4MG) has affinity for glial EAATs, we employed [(3)H]4MG to define the characteristics of EAATs in cultured murine astrocytes and describe new approaches to analyze EAAT function. Specific binding of [(3)H]4MG in astrocytic membranes at 4 degrees C represented 90% of total binding. Binding was rapid (apparent t(1/2) approximately 7 min) and saturable. Saturation and Scatchard analyses indicated a single binding site (n(H) = 0.8) with a K(d) of 6.0 +/- 1.5 microM and B(max) = 9.7 +/- 2.9 pmol/mg protein. Binding of [(3)H]4MG to astrocytic homogenates was Na(+)-dependent and inhibited by K(+). Compounds acting at EAATs, such as L-glutamate (Glu), D-aspartate (D-Asp), L-(2S,3S,4R)-2-(carboxycyclopropyl)glycine and L-trans-pyrrolidine-2,4-dicarboxylate displaced binding to nonspecific levels. L-Serine-O-sulphate, an EAAT1-preferring ligand, fully displaced binding of [(3)H]4MG. In contrast, inhibitors having preferential affinity for EAAT2, L-threo-3-methylglutamate, dihydrokainate, and kainate, were relatively ineffective binding displacers. Agonists and antagonists for Glu receptors failed to significantly inhibit [(3)H]4MG binding. Studies with [(3)H]D-Asp reinforced evidence that [(3)H]4MG was binding to EAATs. These data were consistent with Western blot analyses, which indicated abundant expression of EAAT1 but not EAAT2. [(3)H]4MG was also accumulated rapidly (apparent t(1/2) approximately 4 min) into whole astrocytes by a sodium- and temperature-sensitive process (K(m) of 146 +/- 24 microM, V(max) = 336 +/- 27 nmol/mg protein/min), which possessed an EAAT1-like pharmacologic profile. These findings confirm that 4MG is a substrate for EAAT1 and that the binding assay developed using [(3)H]4MG can be utilized in various preparations including cultured astrocytes.

Astrocyte mGlu(2/3)-mediated cAMP potentiation is calcium sensitive: studies in murine neuronal and astrocyte cultures.

Signal transduction mechanisms of group II metabotropic glutamate receptors (mGlu(2/3)) remains a matter of some controversy, therefore we sought to gain new insights into its regulation by studying cAMP production in cultured neurons and astrocytes, and by examining inter-relationships of mGlu(2/3)-induced signalling with cellular calcium and various signalling cascades. mGlu(2/3) agonists 2R,4R-4-aminopyrrolidine-2,4-dicarboxylic acid (2R,4R-APDC) and (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY379268) inhibited 10 microM forskolin-stimulated production of cAMP in murine cortical neurons, striatal neurons and forebrain astrocytes in the absence of extracellular Ca(2+). These agonists potentiated cAMP production in the presence of 1.8 mM Ca(2+) in astrocytes only. This potentiation was dependent on the extracellular Ca(2+) concentration (0.001-10 mM) and inhibited by the mGlu(2/3) antagonist LY341495 (1 microM), adenosine deaminase (1 U/ml) and the adenosine A(2A) receptor antagonist ZM241385 (1 microM). Pre-incubation with the phospholipase C (PLC) inhibitor U73122 (10 microM), L-type Ca(2+)-channel blockers nifedipine (1 microM) and nimodipine (1 microM), the calmodulin kinase II (CaMKII) inhibitor KN-62 (10 microM) or pertussis toxin (100 ng/ml) inhibited this potentiation. In the absence of 1.8 mM Ca(2+), thapsigargin (1 microM) facilitated the potentiation of cAMP production. Measurement of the Ca(2+)-binding dye Fluo-3/AM showed that, compared to Ca(2+)-free conditions, thapsigargin and 1.8 mM Ca(2+) elevated [Ca(2+)](i) in astrocytes; the latter effect being prevented by L-type Ca(2+)-channel blockers. Potentiation of cAMP production was also demonstrated when astrocytes were stimulated with the beta-adrenoceptor agonist isoprenaline (10 microM) in the presence of 1.8 mM Ca(2+), but not with the adenosine agonist NECA (10 microM) or the group I mGlu receptor agonist DHPG (100 microM). BaCl(2) (1.8 mM) in place of Ca(2+) did not facilitate forskolin-stimulated mGlu(2/3)-potentiation of cAMP. In short, this study in astrocytes demonstrates that under physiological Ca(2+) and adenylate cyclase stimulation an elevation of cAMP production is achieved that is mediated by PLC/IP(3)- and CaMKII-dependent pathways and results in the release of endogenous adenosine which acts at G(s) protein-coupled A(2A) receptors. These findings provide new insights into mGlu(2/3) signalling in astrocytes versus neurons, and which could determine the functional phenotypy of astrocytes under physiological and pathological conditions.

Evaluation of drugs acting at glutamate transporters in organotypic hippocampal cultures: new evidence on substrates and blockers in excitotoxicity.

Removal of L-glutamate (Glu) from the synapse is critical to maintain normal transmission and to prevent excitotoxicity, and is performed exclusively by excitatory amino acid transporters (EAATs). We investigated the effects of substrates and blockers of EAATs on extracellular Glu and cellular viability in organotypic cultures of rat hippocampus. Seven-day treatment with a range of drugs (L-trans-pyrrolidine-2,4-dicarboxylate, (2S,4R)-4-methyl-glutamate, (+/-)-threo-3-methylglutamate and DL-threo-beta-benzyloxyaspartate), in the presence of 300 microM added Glu, resulted in increased extracellular Glu and a significant correlation between Glu concentration and cellular injury (as indicated by lactate dehydrogenase release). In contrast, (2S,3s,4R)-2-(carboxycyclopropyl)glycine (L-CCG-III) exerted a novel neuroprotection against this toxicity, and elevations in extracellular Glu were not toxic in the presence of this compound. Similar results were obtained following two-week treatment of cultures without added Glu. Whilst blockade of GLT-1 alone was relatively ineffective in producing excitotoxic injury, heteroexchange of Glu by EAAT substrates may exacerbate excitotoxicity.