Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Induction of long-term depression (LTD) in rat striatal slices revealed that this form of synaptic plasticity is coupled to an increased expression of tissue-plasminogen activator (t-PA) mRNA, as detected by the mRNA differential display technique. To further investigate the involvement of this gene in synaptic remodelling following striatal LTD, we recorded electrical activity from mice lacking the gene encoding t-PA (t-PA-KO) and from wild-type (WT) mice. Tetanic stimulation induced LTD in the large majority of striatal neurons recorded from WT mice. Conversely, LTD was absent in a significant proportion of striatal neurons obtained from mice lacking t-PA. Electrophysiological recordings obtained from hippocampal slices in the CA1 area showed that mainly the late phase of long-term potentiation (LTP) was reduced in t-PA-KO mice. Learning and memory-related behavioural abnormalities were also found in these transgenic mice. Disruption of the t-PA gene, in fact, altered both the context conditioning test, a hippocampus-related behavioural task, and the two-way active avoidance, a striatum-dependent task. In an open field object exploration task, t-PA-KO mice expressed deficits in habituation and reactivity to spatial change that are consistent with an altered hippocampal function. Nevertheless, decreased rearing and poor initial object exploration were also observed, further suggesting an altered striatal function. These data indicate that t-PA plays a critical role in the formation of various forms of synaptic plasticity and memory.
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PMID:Tissue plasminogen activator controls multiple forms of synaptic plasticity and memory. 1076 31

Use of the anticancer antibiotic doxorubicin continues to be limited by its cumulative dose-related cardiotoxicity. Our study reports inhibition of myocardial intracellular calcium-independent phospholipase A(2) (iPLA(2)) activity by clinically relevant concentrations of the drug. The effect was first shown in vitro using suspensions of freshly isolated rat and rabbit cardiomyocytes. Addition of 0.1-10 microM doxorubicin to these cells led to a concentration- and time-dependent inhibition of total iPLA(2), as measured using (16:0, [(3)H]18:1) plasmenylcholine and phosphatidylcholine substrates in the presence or absence of calcium. Subcellular fractionation into cytosolic and membrane fraction revealed that the drug selectively inhibits membrane-associated iPLA(2) activity, without altering activity of the cytosolic enzyme. Doxorubicin treatment of cells prelabeled with [H(3)]arachidonic acid led to a depression of baseline arachidonic acid release levels, corroborating iPLA(2) inhibition. Reducing agents blocked PLA(2) inhibition in cardiomyocyte suspensions, suggesting that the doxorubicin effect is mediated by oxidation of susceptible cysteines. In vivo experiments, in which adults rats were i.v. injected with a bolus dose of 4 mg/kg doxorubicin, confirmed in vitro findings, revealing a 2-fold decrease in membrane-associated Ca(2+)-independent iPLA(2) activity in the heart tissue of treated animals. The observed phenomenon has important implications for myocyte signaling cascades and membrane remodeling.
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PMID:Clinical concentrations of doxorubicin inhibit activity of myocardial membrane-associated, calcium-independent phospholipase A(2). 1135 21

The effects of Pa-1G, a phospholipase A(2) (PLA(2)) from the venom of the Australian king brown snake (Pseudechis australis) were determined on the release of acetylcholine, muscle resting membrane potential and motor nerve terminal action potential at mouse neuromuscular junction. Intracellular recording from endplate regions of mouse triangularis sterni nerve-muscle preparations revealed that Pa-1G (800 nM) significantly reduced the amplitude of endplate potentials within 10 min exposure. The quantal content of endplate potentials was decreased to 58+/-6% of control after 30 min exposure to 800 nM Pa-1G. The toxin also caused a partial depolarisation of mouse muscle fibres within 60 min exposure. Extracellular recording of action potentials at motor nerve terminals showed that Pa-1G reduced the waveforms associated with both sodium and potassium conductances. To investigate whether this was a direct or indirect effect of the toxin on these ionic currents, whole cell patch clamp experiments were performed using human neuroblastoma (SK-N-SH) cells and B82 mouse fibroblasts stably transfected with rKv1.2. Patch clamp recording experiments confirmed that potassium currents sensitive to alpha-dendrotoxin recorded from B82 cells and sodium currents in SK-N-SH cells were not affected by the toxin. Since neither facilitation of acetylcholine release at mouse neuromuscular junction nor depression of potassium currents in B82 cells has been observed, the apparent blockade of potassium currents at mouse motor nerve endings induced by the toxin is unlikely to be due to a selective block of potassium channels.
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PMID:An electrophysiological study on the effects of Pa-1G (a phospholipase A(2)) from the venom of king brown snake, Pseudechis australis, on neuromuscular function. 1160 81

Fluoxetine, a selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitor, is used widely to treat depression and related disorders. By inhibiting presynaptic 5-HT reuptake, fluoxetine is thought to act by increasing 5-HT in the synaptic cleft, thus 5-HT binding to postsynaptic 5-HT(2A/2C) receptors. These receptors can be coupled via a G-protein to phospholipase A(2) (PLA(2)), which when activated releases the second messenger arachidonic acid from synaptic membrane phospholipids. To image this activation, fluoxetine (10 mg/kg) or saline vehicle was administered i.p. to unanesthetized rats, and regional brain incorporation coefficients k(*) of intravenously injected radiolabeled arachidonic acid were measured after 30 min. Compared with vehicle, fluoxetine significantly increased k(*) in prefrontal, motor, somatosensory, and olfactory cortex, as well as in the basal ganglia, hippocampus, and thalamus. Many of these regions demonstrate high densities of the serotonin reuptake transporter and of 5-HT(2A/2C) receptors. Brain stem, spinal cord, and cerebellum, which showed no significant response to fluoxetine, have low densities of the transporters and receptors. The results show that it is possible to image quantitatively PLA(2)-mediated signal transduction in vivo in response to fluoxetine.
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PMID:Imaging brain phospholipase A2-mediated signal transduction in response to acute fluoxetine administration in unanesthetized rats. 1278 22

Depression and anxiety are prospectively associated with cardiac morbidity and mortality. Increased clotting diathesis may mediate this link. We hypothesized that there would be an association between mood and hemostatic changes that occur during and following recovery from acute mental stress. Forty-eight community-dwelling elderly subjects underwent a laboratory speech stressor task. Plasma von Willebrand factor (vWF), thrombin/antithrombin III (TAT) complexes, D-dimer, tissue-type plasminogen activator (t-PA), and type I plasminogen activator inhibitor (PAI-1) were measured at rest, after conclusion of the speech, and 14 min afterwards (recovery). Mood was assessed with the Hamilton Rating Scales for Depression (Ham-D) and Anxiety (Ham-A). Mental stress elicited a hypercoagulable state as evidenced by increases in TAT and D-dimer, and by a decrease in t-PA. Overall, hypercoagulability had increased after recovery. Ham-D scores and Ham-A scores correlated with increases in D-dimer over the testing interval (i.e. area under the curve). Ham-A (but not Ham-D) uniquely explained 8% and 17% of the variance in resting D-dimer and D-dimer area under the curve, respectively. The independent association of anxiety symptoms with resting and stress-induced fibrin formation (D-dimer) may be a mechanism linking mood with cardiovascular disease risk in the elderly.
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PMID:Effects of depressive symptoms and anxiety on hemostatic responses to acute mental stress and recovery in the elderly. 1515 51

Neuroprotective therapies and tissue plasminogen activator (t-PA) have limited application for most stroke patients and thus rehabilitation is the primary treatment option for improving recovery of function. Following brain injury, environmental enrichment, pharmacological and rehabilitative treatments can markedly alter neuronal plasticity and behavioral recovery even when delayed by several weeks after the insult. Fluoxetine has been given to stroke patients to combat depression but its effects on recovery of function are not known. Functional magnetic resonance imaging reveals that fluoxetine alters brain activity and modulates motor performance in stroke patients in a use-dependent fashion. Several antidepressants, including fluoxetine, increase growth factors and other proteins associated with plasticity, such as brain-derived neurotrophic factor (BDNF). In this study, we examined whether chronic administration of fluoxetine combined with rehabilitation affected recovery of function on 3 separate tests of forelimb reaching, preference and limb coordination after focal ischemia in rats. Ischemia was induced in male Long-Evans rats by intracortical and striatal injections of endothelin-1. Fluoxetine (10 mg/kg/day) combined with rehabilitation therapy (6 h/day) for 4 weeks did not alter the degree or rate of recovery of function compared to non-treated animals. Despite the ability of fluoxetine to alter brain activity and increase growth factors, it does not appear to be an effective pharmacological adjunct to functional recovery after ischemia in rats.
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PMID:Fluoxetine and recovery of motor function after focal ischemia in rats. 1586 86

Endothelial function, measured noninvasively by brachial artery flow-mediated dilatation (FMD), has been shown to be impaired in patients with systemic lupus erythematosus (SLE). We hypothesized that depressed FMD in SLE patients is associated with increased levels of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of fibrinolysis and regulator of vasoactivity. In this cross-sectional study of female SLE patients under the age of 55, putative markers of cardiovascular disease (CVD) such as PAI-1 were measured in addition to lupus-related disease activity (SLEDAI). The primary outcome, FMD, was measured using high-resolution ultrasound of the brachial artery gated to the R wave to determine endothelial-dependent vasomotion. Endothelial-independent vasomotion was measured in response to nitroglycerin (NMD). Seventy-six female SLE patients, mean age 38.3 +/- 9.4 years, were included. All patients demonstrated normal NMD responses, indicating that depression of FMD was related to decreased endothelial nitric oxide production. Increased PAI-1 was related to depressed FMD by univariate regression (P = 0.004). In a multivariable regression model adjusting for t-PA (tissue plasminogen activator)/PAI-1 ratio, SLEDAI, age at visit, family history of cardiovascular disease, SLE disease duration and body mass index, every 1 ng/mL increase in PAI-1 was associated with a reduction of 0.07 units FMD (P = 0.039). PAI-1 was associated with impaired endothelial dysfunction, after controlling for several potential confounders. Given the high incidence of cardiovascular disease in SLE, further investigation of the role of subclinical markers of CVD is needed.
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PMID:Plasminogen activator inhibitor-1 is associated with impaired endothelial function in women with systemic lupus erythematosus. 1612 68

The primary objective of this 9-week open-label extension trial was to assess the effects of risperidone monotherapy in patients with acute bipolar I disorder who completed treatment in two preceding 3-week double-blind trials. Patients with DSM-IV bipolar I disorder, experiencing an acute manic episode, received a flexible dose of risperidone (1-6 mg/day) or placebo in two independent double-blind, randomized, 3-week monotherapy trials. Completers who required ongoing treatment were eligible to enter this open-label 9-week extension trial during which all patients received risperidone. The primary efficacy measure was the mean change in the Young Mania Rating Scale (YMRS) total score. Secondary efficacy measures included the Clinical Global Impressions-Severity Scale, Montgomery-Asberg Depression Rating Scale, Positive and Negative Syndrome Scale and Global Assessment Scale. Safety assessments included adverse event reports, laboratory tests, and the Extrapyramidal Symptom Rating Scale (ESRS). Of the 283 patients who entered the extension study, 160 had previously received risperidone (RIS/RIS) in the acute treatment trial and 123 had received placebo (PLA/RIS). This study was completed by 71% of these patients. The mean+/-SE modal dose of risperidone was 4.6+/-1.5 mg/day. Patients in both the RIS/RIS and PLA/RIS groups improved significantly at the endpoint of the 9-week open-label study compared to their open-label baseline scores (-5.2+/-0.69, P<0.001 and -9.12+/-1.44, P<0.001, respectively) on the YMRS. Furthermore, changes from double-blind baseline to open-label endpoint were -29.4+/-1.0 in the RIS/RIS group and -23.9+/-1.4 in the PLA/RIS group. Significant improvements from both double-blind and open-label baseline were seen at week 1 of the open-label trial (P<0.001) and at each subsequent timepoint. A similar pattern was observed on the secondary measures of efficacy. Most frequent adverse events were extrapyramidal disorder (18%) and somnolence (12%). Most adverse events were mild or moderate in severity. The mean score for the Parkinsonism subscale of the ESRS was 1.1 at open-label baseline, and decreased by 0.1 at endpoint. Mean increase in body weight from open-label baseline was 0.6 kg in patients treated with placebo in the preceding double-blind trial and 1.2 kg in patients previously treated with risperidone. Risperidone treatment was well tolerated and resulted in further improvement during the 9-week extension, beyond the 3 weeks of acute treatment. Patients switched from placebo to risperidone improved markedly. Risperidone treatment did not induce depression.
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PMID:An open-label extension trial of risperidone monotherapy in the treatment of bipolar I disorder. 1631 12

Serotonergic 5-HT(2A/2C) receptors can be coupled to phospholipase A(2) (PLA(2)) activation to release the second messenger, arachidonic acid (AA), from membrane phospholipids. We wished to see if this signaling process in rat brain would be altered by chronic administration followed by 3days of washout of the selective serotonin reuptake inhibitor, fluoxetine. We injected [(3)H]AA intravenously in unanesthetized rats and used quantitative autoradiography to determine the incorporation coefficient k() for AA (regional brain radioactivity/integrated plasma radioactivity), a marker of PLA(2) activation, in each of 86 brain regions. k() was measured following acute i.p. saline or (+/-)-2,5-dimethoxy-4-iodophenyl-2-aminopropane (DOI, 1.0mg/kg i.p.), a 5-HT(2A/2C) receptor agonist, in rats injected for 21days with 10mg/kg i.p. fluoxetine or saline daily, followed by 3days without injection. Acute DOI produced statistically significant increments in k() in brain regions with high densities of 5-HT(2A/2C) receptors, but the increments did not differ significantly between the chronic fluoxetine- and saline-treated rats. Additionally, chronic fluoxetine compared with saline widely and significantly increased baseline values of k(). These results suggest that 5-HT(2A/2C) receptor-initiated AA signaling is unaffected by chronic fluoxetine plus 3days of washout in the rat, but that baseline AA signaling is nevertheless upregulated. This upregulation likely occurs independently of significant active drug in brain, considering the short brain half-lives of it and its norfluoxetine metabolite. Such upregulation may contribute to fluoxetine's efficacy against human depression.
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PMID:Chronic fluoxetine upregulates arachidonic acid incorporation into the brain of unanesthetized rats. 1651 30

We describe a case of sudden and severe pulseless electrical activity in a 30 year old woman which was managed successfully with reteplase and heparin one day following an anterior cruciate ligament repair. The presentation of a sudden collapse with ECG findings of S1Q3T3, early precordial lead ST depression and partial right bundle branch block were indicative of an acute pulmonary embolus. The cardiopulmonary collapse necessitated rapid treatment in the absence of confirmatory investigations. Reteplase (10 U stat followed by 10 U at 30 minutes) led to a dramatic improvement in the cardiovascular status of the patient. One day following the cardiac arrest the patient was extubated and responding normally. A spiral CT performed later confirmed multiple small embolic defects in the lower pulmonary arteries of both lower lung zones. This case highlights the utility of reteplase in the management of an acute pulmonary embolism and in an emergency, recent surgery is not necessarily a contraindication to its use.
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PMID:Life threatening massive pulmonary embolism treated with reteplase: a case report. 1659 9


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