@article{SirenHeldmanDoronetal.1992, author = {Sir{\´e}n, Anna-Leena and Heldman, Eliahu and Doron, David and Yue, Tian-Li and Liu, Yong and Feuerstein, G. and Hallenbeck, JM}, title = {Release of proinflammatory and prothrombbtic mediators in the brain and peripheral circulation in spontaneously hypertensive and normotensive Wistar-Kyoto rats}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47469}, year = {1992}, abstract = {Background and Purpose: We reported previously that stroke risk factors prepared the brain stem for the development of ischemia and hemorrhage and induced the production of tumor necrosis factor following an intrathecal injection of Iipopolysaccharide, a prototypic monocyte-activating stimulus. This study evaluates whether blood or brain cells of hypertensive rats produce more proinflammatory and prothrombotic mediators than do blood or brain cells of normotensive rats. MethotJs: Levels of tumor necrosis factor, platelet-activating factor, 6-ketoprostaglandin F1a, and thromboxane B2 in the cerebrospinal fluid and blood of spontaneously hypertensive and normotensive Wistar-Kyoto rats were monitored before and after achallenge with Iipopolysaccharide. Results: Little or no activity from these media tors was found in the cerebrospinal fluid or blood of saline-injected control animals. Intravenous administration of Iipopolysaccharide (0.001, 0.1, and 1.8 mg/kg) produced dose-dependent increases in blood levels of all mediators in hypertensive rats. In normotensive rats the levels were less than in hypertensive rats and were not c1early dose-related. When Iipopolysaccharide was injected intracerebroventricularly, more tumor necrosis factor was measured in the cerebrospinal fluid than in the blood, suggesting local synthesis of this cytokine. Levels of tumor necrosis factor and platelet-activating factor in the cerebrospinal fluid were higher in hypertensive than in normotensive rats. The thromboxane A2/prostacyclin ratio was not aItered significantly between the two rat strains. Conclusions: It is suggested that the higher incidence of brain stem ischemia and hemorrhage after the intrathecal injection oflipopolysaccharide in hypertensive rats than in normotensive rats might be related to the higher levels of the two cytotoxic factors tumor necrosis factor and platelet-activating factor produced in response to such challenge.}, subject = {Gehirn}, language = {en} } @article{SirenFeuerstein1992, author = {Sir{\´e}n, Anna-Leena and Feuerstein, G.}, title = {The Opioid System in circulatory control}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63045}, year = {1992}, abstract = {Opioid peptidesandmultiple opioid receptors are found in brain cardiovascular nuclei, autonomic ganglia, the heart, and blood vessels, and opioids induce potent cardiovascular changes. The role of endogenaus opioids in normal cardiovascular homeostasis is unclear; however, current data suggest opioid involvement in stress.}, subject = {Neurobiologie}, language = {en} } @article{PaakkariPaakkariFeuersteinetal.1992, author = {Paakkari, P. and Paakkari, I. and Feuerstein, G. and Sir{\´e}n, Anna-Leena}, title = {Evidence for differential opioid µ\(_1\)- and µ\(_2\)-receptor regulation of heart rate in the conscious rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63017}, year = {1992}, abstract = {The possibility that \(\mu\)Opioid-induced tachycardia and bradycardia could be mediated by different subtypes of the \(\mu\)·receptor was studied in conscious Sprague-Dawley rats. The selective \(\mu\)·receptor agonist dermorphin and its analog, TAPS (Tyr-o-Arg-Phe-sarcosine), a putative \(\mu _1\)-receptor agonist, were given centrally. Tyr-o-Arg-Phe-sarcosine increased the heart rate, the response being inversely correlated to the dose (an increase of 71 ± 22, 49 ± 14 and 30 ± 17 beats/min at doses of 0.3, 3 and 30 pmol, respectively). Dermorphin induced less clear changes in heart rate (maximum increase of 39 ± 14 beats/min at the dose of 1 pmol). Aftertreatment with the Jl 1-selective antagonist naloxonazine (NAZ), TAPS 30 pmol and dennorphin I pmol decreased heart rate by -22 ± 10 and -24 ± 7 bpm, respectively. The bradycardic effect oflarger doses of dennorphin was potentiated by NAZ (from -25 ± 8 to -97 ± 22 bpm) but abolished by the non-selective antagonist naloxone. These data suggest that the high affinity \(\mu _1\)-opioid receptors mediate tachycardic responses and \(\mu _2\)-receptors mediate bradycardic responses.}, subject = {Neurobiologie}, language = {en} } @article{DoronMcCarronHeldmanetal.1992, author = {Doron, D. A. and McCarron, D. M. and Heldman, E. and Sir{\´e}n, Anna-Leena and Spatz, M. and Feuerstein, G. and Pollard, H. B. and Hallenbeck, J. M.}, title = {Comparison of stimulated tissue factor expression by brain microvascular endothelial cells from normotensive (WKY) and hypertensive (SHR) rats}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63032}, year = {1992}, abstract = {The amounts of tissue factor (TF) expressed by brain microvascular endothelial cells (BMECs) from normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were compared after stimulating the cells with different doses of lipopolysaccharide (LPS), thrombin, phorbol myristic acid (PMA), Ca\(^{2+}\)·ionophore (A23187), or tumor necrosis factor (TNF) and interleukin·l (IL.l). Treatment ofcultured BMECs fron. WKY and SHR with all of these factors dose·dependently increased their total amount of TF; no substantive differences in the Ieveis of enhanced TF expression were observed between WKY and SHR BMECs. We conclude that stimulated endothelium from rats with hypertension, a major stroke risk factor, is not hyperresponsive with respect to TF expression when compared to normotensive controls.}, subject = {Neurobiologie}, language = {en} }