Brain research bulletin
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Brain research bulletin · Jan 2010
Novel approach to demonstrate high efficacy of mu opioids in the rat vas deferens: a simple model of predictive value.
14-O-Methyloxymorphone and 14-methoxymetopon were reported as highly selective and potent micro opioid receptor agonists. The aim of this study was to demonstrate the opioid activity of these compounds in vitro and in vivo in comparison to oxymorphone, morphine and DAMGO. The micro opioid receptor efficacy, full or partial agonist nature of opioids was analyzed in the rat vas deferens (RVD) bioassay. ⋯ Both, 14-O-methyloxymorphone and 14-methoxymetopon are highly efficacious micro opioid receptor agonists in the RVD exhibiting full micro agonist properties. The RVD tissue contains mu receptors indicated by the comparable K(e) values of the micro antagonist naltrexone against DAMGO in the MVD. RVD may be a good alternative to assess the mu receptor efficacy of opioid agonists providing a more physiological environment for the ligand-receptor interaction than other efficacy measuring methods such as the [(35)S]GTPgammaS binding assay.
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Brain research bulletin · Jan 2010
Prognostic value of biochemical markers of brain damage and oxidative stress in post-surgical aneurysmal subarachnoid hemorrhage patients.
The aim of this study is to determine effective biochemical markers and optimal sampling timing for prediction of neurological prognosis in post-surgical aneurysmal subarachnoid hemorrhage (SAH) patients. Subjects were a sequential group of SAH patients admitted to our centre who underwent aneurysm clipping before Day 3 and who received a cerebrospinal fluid (CSF) drain. CSF samples from 32 patients were collected on Days 3, 7, and 14. ⋯ The area under the receiver-operating characteristic (ROC) curve for MDA on Day 14 was 0.841. For a threshold of 0.3 microM, sensitivity and specificity were 0.875 and 0.750, respectively. Our findings suggest that these biochemical markers, especially MDA, show significant promise as predictors of neurological outcome in clinical practice.
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Brain research bulletin · Jan 2010
Sensitization of voltage activated calcium channel currents for capsaicin in nociceptive neurons by tumor-necrosis-factor-alpha.
It is known that application of tumor-necrosis-factor-alpha (TNF-alpha) sensitizes neuronal calcium channels for heat stimuli in rat models of neuropathic pain. This study examines whether TNF-alpha modulates the capsaicin-induced effects after transient receptor potential vanilloid (TRPV)-1 receptor activation on voltage activated calcium channel currents (I(Ca(V))). TRPV-1 receptors are activated by heat and play an important role in the pathogenesis of thermal hyperalgesia in neuropathic pain syndromes, while voltage activated channels are essential for transmission of neuronal signals. ⋯ While L-type (36.6+/-5.2%) and P/Q-type currents (35.6+/-4.1%) are also sensitized by TRPV-1 activation, N-type channel currents are most sensitive (74.5+/-7.3%). The capsaicin-induced shift towards the hyperpolarizing voltage range does not occur when TNF-alpha is applied. Summarizing, TNF-alpha sensitizes nociceptive neurons for capsaicin.