@article{SirenEimerlFeuerstein1989, author = {Sir{\´e}n, Anna-Leena and Eimerl, J. and Feuerstein, G.}, title = {L-649,923 : An antagonist of cardiac and vascular leukotriene D\(_4\) receptors}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63134}, year = {1989}, abstract = {The capacity of L-649,923-sodium ( ßS, -yR * )-4-(3-( 4-acetyl-3-hydroxy-2-propylphenoxy)propylthio)-- y-hydroxy-ß-methylbenzene butanoate-to block vascular receptors of leukotriene D\(_4\) ( L TD\(_4\)) was examined in the conscious rat. Hindquarter (HQ), renal, and mesenteric blood flow and vascular resistance were evaluated in the conscious rat chronically equipped with miniaturized Doppler probes for organ blood flow measurement by directional pulsed Doppler technique. In addition, cardiac outpul was measured by thermodilution technique in conscious rats equipped with minithermistors in the ascending aorta. Systemic hemodynamic variables. mean arterial pressure, and heart rate were monitored through femoral catheters. L TD\(_4\) (I or 10 \(\mu\)g/kg) produced a marked dose dependent increase in the mesenteric vascular resistance associated with a marked decrease in blood flow whereas no consistent effects were demonstrated in the renal circulation. L TD\(_4\) • at I \(\mu\)g/kg. increased the HQ blood flow whereas the higher dose of LTD\(_4\) produced a biphasic response: an early increase followed by a decrease in blood flow. Infusion of L TD\(_4\) • 3 \(\mu\)g/kg per min over 10 min decreased cardiac output and increased total peripheral resistance. L-649,923 (10 or 30 mg/kg, i.v.) effectively blocked the L TD4-induced mesenteric constriction and the second I phase of HQ vasoconstriction but did not modify the , LTD\(_4\) induced HQ vasodilation. L-649,923 also effectively attenuated the cardiac effects of LTD\(_4\) infusion. I These studies suggest that L-649,923 could preserve cardiac and vascular functions in pathologic states mediated by cysteinylleukotrienes, such as traumatic or endotoxin shock. Key Words: Leukotriene D4 -Cardiovascular system- Leukotriene antagonist- Mesenteric blood tlow-Renal blood flow-Hindquarter blood flowAnaphylaxis.}, subject = {Neurobiologie}, language = {en} } @article{SirenFeuerstein1990, author = {Sir{\´e}n, Anna-Leena and Feuerstein, G.}, title = {Cardiovascular effects of anatoxin-a in the conscious rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63103}, year = {1990}, abstract = {Cardiovascular Effects of Anatoxin-A in the Conscious Rat. SJREN, A.-L., AND FEUERSTEIN, G. (1990). Toxicol. Appl. Pharmacol. 102,91-100. The effects ofanatoxin-A on mean arterial pressure (MAP), heart rate, cardiac index (CI), and blood flow (BF) in hindquarter (HQ), renal (R). and mesenteric (M) vascular beds were studied after intravenous (iv) and intracerebroventricular (icv) administration in the conscious rat. The pharmacological profile of anatoxin-A was further compared to nicotine administered iv and icv. MAP and heart rate were measured from femoral artery, CI by thermodilution method, and blood flow by Doppler velocimetry. Anatoxin-A and nicotine (30, 100 and 300 1-!g/kg iv) produced an increase in MAP with concomitant bradycardia. The highest doses increased Cl. MBF and RBF decreased due to a vasoconstriction in M and R vasculature. These effects were attenuated by the ganglion blocker chlorisondamine (5 mg/kg, iv). Anatoxin-A ( 100 1-!g/k~ iv) increased plasma epinephrine Ievels by 2- fold with virtually no effect on norepinephrine whereas nicotine ( 100 ~oLg/kg, iv) increased plasma epinephrine and norepinephrine by 20- to 30-fold. Central administration of anatoxin-A and nicotine (30-100 ,ug/kg icv) increased MAP with no effect on heart rate and produced M and R vasoconstriction. In summary, the present study demonstrates that anatoxin-A acts as a nicotinic cholinergic agonist in the c.onscious rat after both systemic and centrat administration. Anatoxin-A and nicotine produced pressor and reno-splanchnic vasoconstrictor responses and at high doses increased cardiac output. These effects were mediated by activation ofthe nicotinic receptors in the adrenal medulla and sympathetic ganglia. However, marked differences were found in the potency ofanatoxin-A versus nicotine to stimulate the sympathoadrenomedullary axis.}, subject = {Neurobiologie}, language = {en} } @article{PaakkariPaakkariSirenetal.1990, author = {Paakkari, P. and Paakkari, I. and Sir{\´e}n, Anna-Leena and Feuerstein, G.}, title = {Respiratory and locomotor stimulation by low doses of dermorphin - a Mu\(_1\)-receptor mediated effect}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63110}, year = {1990}, abstract = {The selective opioid mu receptor agonist dermorphin increased the locomotor activity of rats dose dependently at 1 0 to 1 00 pmol/kg i.c.v. Respiratory rate, relative tidal volume and respiratory minute volume also increased unrelated to changes in locomotor activity. Higher doses, on the other hand, produced catalepsy and respiratory depression. Pretreatment of the rats with the mu,-selective antagonist naloxonazine (10 mg/kg i.v.) blocked the stimulant locomotor and respiratory effects of low doses of dermorphin (1 0--1 00 pmol/kg), but potentiated the respiratory depressant effect of a high dose (1 0 nmol/kg) of dermorphin. The selective benzodiazepine antagonist flumazenil (5 mg/kg), which has been shown previously to antagonize catalepsy and respiratory depression produced by relatively high doses of dermorphin, did not antagonize the respiratory or locomotor stimulant effect of dermorphin. The data suggest that mu\(_1\)-opioid receptors are responsible for the low dose stimulant effects of dermorphin on locomotor activity and respiration whereas mu\(_2\) receptors mediate the respiratory depressant effect of dermorphin.}, subject = {Neurobiologie}, language = {en} } @article{VonhofSirenFeuerstein1990, author = {Vonhof, S. and Sir{\´e}n, Anna-Leena and Feuerstein, Giora}, title = {Volume-dependent spatial distribution of microinjected thyrotropin-releasing hormone (TRH) into the medial preoptic nucleus of the rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47421}, year = {1990}, abstract = {The present study was performed to qua ntify the distribution of a peptide neurotransmitter after microinjection into the medial preoptic area (POM), using a technique suitable for conscious animal preparations. The results indicate that only 50-ni volumes of injected tracer were sufficiently localized with 77 ± 9\% recovery in the POM. Injections of higher volumes resulted in an increasing spread of tracer into distant anatomical regions and structures, including the needle tract and cerebral ventricles. The amount of tracer localized in the POM decreased to 38±4\% (200 nl) (P < 0.05) and 41 ±8\% (500 nl) (P <0.05), respectively. The data suggest that the volume of injection is critical for intraparenchymal injections into structures of a diameter of I mm or less, such as the POM and should not exceed 50 nl in conscious animal preparations.}, subject = {Neurophysiologie}, language = {en} } @article{ShuaibXuCrainetal.1990, author = {Shuaib, A. and Xu, K. and Crain, B. and Sir{\´e}n, Anna-Leena and Feuerstein, Giora and Hallenbeck, J. and Davis, JN}, title = {Assessment of damage from implantation of microdialysis probes in the rat hippocampus with silver degeneration staining}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47433}, year = {1990}, abstract = {We used a sensitive silver degeneration staining method to study the effects of insertion of microdialysis probes in rat dorsal hippocampus and neocortex. Nine animals were sacrificed 24 h, 3 days or 7 days after implantation of dialysis tubing. Although mild neuronal cell death and small petechial hemorrhages were seen in elose proximity to the implantation site, the striking finding was the presence of degenerating axons both adjacent to the implantation site and in remote sites such as the corpus callosum and contralateral hippocampus. The observed changes could alter brain function near or remote from the implantation site and should be considered in analysis of dialysis experiments.}, subject = {Neurophysiologie}, language = {en} } @article{FeuersteinZerbeSiren1991, author = {Feuerstein, G. and Zerbe, R. L. and Sir{\´e}n, Anna-Leena}, title = {Supraoptic nuclei in vasopressin and hemodynamic responses to hemorrhage in rats}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63057}, year = {1991}, abstract = {CARDIOVASCULAR and vasopressin (A VP) responses to hcmorrhagc wcrc studicd in rats with lesions of the hypothalamic supraoptic nuclei (SONL). Bleeding caused hypotension and increase in heart rate (HR) and A VP. SONL rats failed to fully recover from bleeding as compared to normal rats. Plasma A VP in SONL rats was in the normal in basal conditions, but failed to increase to levels attained in normal rats throughout the post-hemorrhage period. These data suggcst that the supraoptic nuclei are the primary regulatory sitcs for A VP release in rcsponse to hemorrhage and that lack of adequate A VP release significantly retards blood pressure recovery after bleeding.}, subject = {Neurobiologie}, language = {en} } @article{SirenFeuerstein1991, author = {Sir{\´e}n, Anna-Leena and Feuerstein, G.}, title = {Hypothalamic opioid µ-receptors regulate discrete hemodynamic functions in the conscious rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63069}, year = {1991}, abstract = {The effect of the selective \(\mu\)-opioid agonist o-Ala\(^2\)-Me-Phe\(^4\)-Gly-ol'-enkephalin (DAGO), injected into the medial preoptic nucleus of hypothalamus, on cardiac output and regional blood flow was studied in the conscious rat and the effect of DAGO on renal sympathetic nerve activity and renal blood flow was studied in anesthetized rats. In conscious rats, injections of DAGO (1 or 10 nmol) into the preoptic nucleus increased the blood pressure in a dose-related manner. The maximum rises of mean arterial pressure and pulse pressure after the larger dose were +23 ± 5 mmHg (mean ±SEM, P < 0.01) and + 17 ± 3 mmHg(P < 0.01), respectively. A small dose (0.1 nmol) increased heart rate ( +47 ± 13 bpm, P < 0.05); thc 1 nmol dosc produced bradycardia (- 39 ± 11 bpm, P < 0.05), while the 10 nmol dose initially decreased heart rate ( -68 ± 15 bpm (P < 0.01) and then gradually increased heart rate to a maximum of + 74 ± 13 bpm, (P < 0.0 1). A long-lasting increase in cardiac output was also elicited by DAGO, with maximum changes after 1 and 10 nmol of + 14 ± 6\% and +22 ± 7\% (P < 0.01), respectively. B1ood flow in the hindquarters increascd after DAGO but the mesenteric and renal blood ftow decreased in a dose-related manner. Significant responscs in hindquarter and mesenteric blood fl.ow after DAGO were independent of systemic hemodynamic responses at the dose ofO.l nmol. The vascular resistance in the hindquarters significantly decreased after a small dose of DAGO while the larger doses dose-dependently increased mesenteric and renal vascular resistance. A crucial role of the sympathetic nervous system in the hemodynamic effects of DAGO was demonstrated: (1) by the profound activation of renal sympathetic nerve activity after injections of DAGO (I nmol/100 nl) into the preoptic nucleus, (2) by blockade of the pressor, tachycardic and regional hemodynamic effects of DAGO (I nmol) by the ganglion blocker ch1orisondamine (5 mg/kg i.v.). The results suggest that the pressor effect of DAGO in preoptic nucleus is due primarily to an increase in cardiac output. The differential changes in blood ftow in organs further suggest that the opioid \(\mu\)-receptors in the preoptic nucleus might be involved in the integration of peripheral blood ftow in the hypothalamus during affective behavior.}, subject = {Neurobiologie}, language = {en} } @article{VonhofSirenFeuerstein1991, author = {Vonhof, S. and Sir{\´e}n, Anna-Leena and Feuerstein, G.}, title = {Central ventilatory effects of thyrotropin-releasing hormone in the conscious rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63075}, year = {1991}, abstract = {Thyrotropin-releasing hormonewas shown to exert potent ventilatory effects after centrat administration. These data, however, were derived from studies using anesthetized animal preparations. Since TRH elicits strong arousal reactions, the observed ventilatory effects of TRH under anesthesia may have been due to nonspecific reduction in the anesthetic state of the animals. In order to clarify the extent to which the reversal of anesthesia may change ventilatory parameters after TRH application, we investigated the effect of TRH on Ventilation rate, relative tidal volume, relative respiratory minute volume, CO\(_2\) production CO\(_2\) consumption, and locomotor activity in the conscious, unrestrained rat. Intracerebroventricular application of TRH induced a dose-dependent, sustained increase in ventilation rate, relative tidal volume, and relative respiratory minute volume of maximally 128\%, 890\%, and 235\%, respectively. In addition, CO\(_2\) production and O\(_2\) consumption were elevated by 4.6 and 11.7 fold, whiJe no significant changes in locomotor activity were observed. The results suggest that TRH stimulates ventilation by a mechanism independent of its analeptic properties.}, subject = {Neurobiologie}, language = {en} } @article{AdeyemoShapiraTombaccinietal.1991, author = {Adeyemo, O. M. and Shapira, S. and Tombaccini, D. and Pollard, H. and Feuerstein, G. and Sir{\´e}n, Anna-Leena}, title = {A goldfish model for evaluation of the neurotoxicit of \(\omega\)-conotoxin GVIA and screening of monoclonal antibodies}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63087}, year = {1991}, abstract = {A Goldfish Model for Evaluation of the Neurotaxicity of \(\omega\)-Conotoxin GVI A and Screening of Monoclonal Antibodies. ADEYEMO, 0. M .. SHAPIRA, S., TOMBACCINI, D., POLLARD, H. 8 .• FEUERSTEIN, G .. AND SIREN, A-L. ( 1991 ). Toxicol. App/. Pharmaco/. 108, 489-496. The neurotoxicity of \(\omega\)-conotoxin (\(\omega\)-CgTx), a potent neuronal voltage-sensitive calcium channel blocker, was measured using a new bioassay. \(\omega\)-CgTx was administered intraperitoneally (ip) to goldfish weighing approximately 1.6 g, and dose-related changes were observed over a 2-hr period. \(\omega\)CgTx induced time- and dose-dependent abnormal swimming behavior (ASB) and mortality. The antitoxin activity of the antiborlies was investigated in vivo by either ( l) preincubation of the antibody with w-CgTx at 4°C overnight, or (2) pretreatment with antibody, 30 min before \(\omega\)CgTx injection in a 10:1 antibody/\(\omega\)-CgTx molar ratio. The LD50 dose of \(\omega\)-CgTx in goldfish was 5 nmol/kg ip, and preincubation of monoclonal antibody (50 nmol/kg ip) with \(\omega\)-CgTx (5 nmol/kg ip) significantly (p < 0.05) reduced mortality. ASB, and toxicity time. The antitoxin activity of the monoclonal antiborlies evidenced in the goldfish bioassay was further tested in the conscious rat. In the rat, the increases in mean arterial pressure and heart rate induced by \(\omega\)-CgTx (0.03 nmol/rat icv) were significantly (p < 0.02 and p < 0.0 l, respectively) attenuated by preincubation of the toxin with the antibody (0.3 nmol/rat). We conclude that the goldfish bioassay provides a simple. accurate, and inexpensive in vivo model for the study of the toxicity of \(\omega\)CgTx}, subject = {Neurobiologie}, language = {en} } @article{SirenVonhofFeuerstein1991, author = {Sir{\´e}n, Anna-Leena and Vonhof, S. and Feuerstein, G.}, title = {Hemodynamic defense response to thyrotropin-releasing hormone injected into medial preoptic nucleus in rats}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63099}, year = {1991}, abstract = {No abstract available}, 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{AdeyemoSiren1992, author = {Adeyemo, M. and Sir{\´e}n, Anna-Leena}, title = {Cardio-respiratory changes and mortality in the conscious rat induced by (+)- and (±)- anatoxin-a}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63027}, year = {1992}, abstract = {0. M. ADEYEMO and A.-L. SIREN. Cardio-respiratory changes and mortality in the conscious rat induced by ( + )- and ( ± )-anatoxin-a. Toxicon 30, 899-905, 1992.-Anatoxin-a (AnTx-a) isapotent nicotinic cholinergic receptor agonist. The relative potencies of the ( + )-AnTx-a and the racemic mixture ( ± )-AnTxa were investigated in the conscious rat by comparing their effects on mean arterial blood pressure (BP), heart rate (HR), blood oxygen and carbon dioxide pressures (p02 and pC02, respective1y), acid-base balance (pH) and mortality. The present experiments show that while both forms of AnTx-a produce dose-dependent increases in BP and decreases in HR, ( + )-AnTx-a is about IO-fo1d morepotent than the optically inactive isomer. ( + )-AnTx-a was also 6-fo1d more potent than ( ± )-AnTx-a in produclog severe hypoxemia, and more than 4-fold as potent as the (±}-AnTx-a in producing significant hypercapnia accompanied with severe acidosis. The approximate median Iethai dose (Ln so) of ( + )-AnTx-a was about 5-fold less than that of ( ± )-AnTx-a. We conclude that ( + )-AnTx-a is more potent than the ( ± )-AnTx-a racemic mixture in causing detrimental cardio-respiratory changes and therefore increased mortality in the rat.}, subject = {Neurobiologie}, 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{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} } @article{SirenMcCarronLiuetal.1993, author = {Sir{\´e}n, Anna-Leena and McCarron, R. M. and Liu, Y. and Barone, F. and Spatz, M. and Feuerstein, G. and Hallenbeck, J. M.}, title = {Perivascular monocyte/macrophage interaction with endothelium as a mechanism through which stroke-risk factors operate to increase stroke likelihood. Research Initiatives in Vascular Disease; SPECIAL COMMUNICATION}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63006}, year = {1993}, abstract = {No abstract available}, subject = {Neurobiologie}, language = {en} } @article{PaakkariPaakkariLandesetal.1993, author = {Paakkari, P. and Paakkari, I. and Landes, P. and Sir{\´e}n, Anna-Leena and Feuerstein, G.}, title = {Respiratory \(\mu\)-Opioid and benzodiazepine interactions in the understrained rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62974}, year = {1993}, abstract = {lnteractions of p-opioid receptors with the benzodiazepine system were studied by examining the modulatory effects of flumazenil (a benzodiazepine antagonist) and alprazolam (a benzodiazepine agonist) on the respiratory effects ofthe opioid peptide dermorphin. Dermorphin, 1-30 nmol administered i.c.v., to conscious, unrestrained rats decreased ventilation rate (VR) and minute volume (MV) dose-dependently. The ventilatory depression was antagonized by naloxone and by the benzodiazepine antagonist flumazenil. The benzodiazepine alprazolam potentiateri the respiratory inhibition of a small (I nmol) dose of dermorphin but antagonized that of a higher dos:~ (3 nmol). The results suggest that the benzodiazepine/GABA receptor complex modulates respiratory depression induced by centrat p-receptor Stimulation in the rat.}, subject = {Neurobiologie}, language = {en} } @article{PaakkariPaakkariVonhofetal.1993, author = {Paakkari, P. and Paakkari, I. and Vonhof, S. and Feuerstein, G. and Sir{\´e}n, Anna-Leena}, title = {Dermorphin analog Tyr-D-Arg\(^2\)-Phe-sarcosine-induces opioid analgesia and respiratory stimulation - the role of Mu\(_1\)- receptors?}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62984}, year = {1993}, abstract = {Tyr-o-Arg\(^2\)-Phe-sarcosine\(^4\) (TAPS), a mu-selective tetrapeptide analog of dermorphin, induced sustained antinociception and stimulated ventilatory minute volume (MV) at the doses of 3 to 100 pmol i.c.v. The doses of 30 and 100 pmol i.c.v. induced catalepsy. The effect of TAPS on MV was in negative correlation with the dose and the maximal response was achieved by the lowest (3 pmol) dose (+63 ± 23\%, P < .05). Morphine, an agonist at both mu\(_1\) and mu\(_2\) sites, at a dose of 150 nmol i.c.v. (equianalgetic to 100 pmol of TAPS decreased the MV by 30\%, due to a decrease in ventilatory tidal volume. The antinociceptive effect of TAPS was antagonized by naloxone and the mu, receptor antagonist, naloxonazine. Naloxonazine also attenuated the catalepsy produced by 1 00 pmol of TAPS i.c. v. and the respiratory Stimulation produced by 3 pmol of TAPS i.c.v. Pretreatment with 30 pmol of TAPS antagonized the respiratory depression induced by the mu opioid agonist dermorphin (changes in MV after dermorphin alone at 1 or 3 nmol were -22 ± 1 0\% and -60 ± 9\% and, after pretreatment with TAPS, +44 ± 11 \% and -18 ± 5\%, respectively). After combined pretreatment with naloxonazine and TAPS, 1 nmol of dermorphin had no significant effect on ventilation. In contrast, pretreatment with a low respiratory stimulant dose (10 pmol i.c.v.) of dermorphin did not modify the effect of 1 nmol of dermorphin. ln conclusion, the antinociceptive, cataleptic and respiratory stimulant effects of TAPS appear to be a related to its agonist action at the mu, opioid receptors. TAPS did not induce respiratory depression (a mu\(_2\) opioid effect) but antagonized the respiratory depressant effect of another mu agonist. Thus, in vivo TAPS appears to act as a mu\(_2\) receptor antagonist.}, subject = {Neurobiologie}, language = {en} } @article{XuNaeveriFrerichsetal.1993, author = {Xu, K. and N{\"a}veri, L. and Frerichs, K. and Hallenbeck, J. M. and Feuerstein, G. and Davis, J. N. and Sir{\´e}n, Anna-Leena}, title = {Extracellular catecholamine levels in rat hippocampus after a selective alpha2-adrenoceptor antagonist or a selective dopamnie uptake inhibitor: Evidence for dopamine release from local dopaminergic nerve terminals}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62997}, year = {1993}, abstract = {The effect of 6-chloro-2,3,4,5-tetrahydro-3-methyi-1-H-3-benzazepine (SKF 86466), a selectlve nonimldazoline alpha-2 adrenoceptor antagonlst, on hippocampal re1ease of norepinephrine and dopamlne in conscious rats was lnvestigated by /n vlvo mlcrodialysis and high-pressure liquid chromatography. Additionally, extracellular concentrations of hippocampal dopamine (DA) and norepinephrtne (NE), durtng Infusion of selective monoamine uptake Inhibitors, were determined in freely moving rats. The basal concentration of NE in the dialysate was 4.9 ± 0.3 pg/20 pl. lntravenous admlnistratlon of 5 or 10 mgJkg of SKF 86466 was associated wlth a transierlt inc:rease (30 min) of 2-fold (12 ± 1 pg/20 ,d; p < .05) and 8-fold (39 ± 3 pg/20 pl; p < .05), respectlvely, in dlalysate NE, whereas a 1-mgfkg dose had no effect. DA was not detected in basal dlalysates, but after the adminlstratlon of 5 or 10 mgJkg of SKF 86466, 3.9 ± 0.4 and 6.4 ± 0.6 pg/20 pl, respectlvely, was present in the dialysates. The rnaxlmum increase in dialysate DA was reached 60 to 90 min after SKF 86466. The DA was not derived from plasma because plasma NE was elevated after the 5 mgJkg dose of SKF 86466 whereas no plasma DA was detected. ln order to determlne whether DA was present in noradrenergic nerve termlnals, the dopamine ß-hydroxylase Inhibitor SKF 1 02698 was administered (50 mgJkg i.p.). The Inhibitor decreased dialysate NE but DA was stin not detected in the dialysate. When SKF 86466 (5 mgJkg t.v.) was adminlstered 4 hr after SKF 102698, DA appeared in the dialysate but there was no lncrease in dialysate NE. Administration through the dialysis probe of the DA uptake Inhibitor, GBR-12909 (0.1 and 1 pM), dose-dependently lnaeased DA Ieveis to 5.7 ± 1.2 and 9.6 ± 2.8 pg/20 pl, respectively. GBR-12909 had no effect on hippocampal NE. Desipramine (5 and 10 pM) lncreased dose-dependently dialysate NE and lncreased DA concentrations to detectable Ieveis (2.7 ± 0.5 and 3.5 ± 0.7 pg/20 ,d, respectively). These results suggest that the a/pha-2 adrenoceptors modulate both NE and DA release in the rat hlppocampus and that DA detected in the hlppocampal dialysate might be released from dopaminergic neurons.}, subject = {Neurobiologie}, language = {en} } @techreport{McCarronDoronSirenetal.1994, author = {McCarron, R. M. and Doron, D. A. and Sir{\´e}n, Anna-Leena and Feuerstein, G. Z. and Heldman, E. and Pollard, H. B. and Spatz, M. and Hallenbeck, J. M.}, title = {Agonist-stimulated release of von Willebrand factor and procoagulant factor VIII in rats with and without risk factors for stroke [Research Report]}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62945}, year = {1994}, abstract = {Lipopolysaccharidc (LPS)-induced (i.v. or i.c.v., 1.8 mg/kg) release of von Willebrand factor (vWF) ·was examined in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. SHR rats releascd significantly (P < 0.05) more vWF than WKY rats in response to LPS. LPS also inhibited factor VIII procoagulant activity (FVIII: c) which may indicate an increase in thrombin activity. Cultured cerebrovascular endothelial cells (EC) derived from both SHR and WKY rats, as weil as human umbilical vein EC (HUVEC) cultures constitutively released vWF. Treatment with agonists including LPS, thrombin and tumor necrosis factor-a (TNFa) did not affect the in vitro secretion of vWF by cerebrovascular EC cultures but significantly upregulated vWF release by HUVEC cultur~s. Preincubation of cerebrovascular EC cultures with interleukin-1 OL-l) ± TNFa or co-culturing in the presence of LPS-activated syngeneic monocytes had no effect on vWF secretion. The findings demoostrate that conditions of hypertension may affect endothelial cells and make them more responsive to agonist Stimulation and thereby increase secretion of vWF, an important factqr in hemostasis as weil as thrombosis. The capacity of LPS to significantly affect the in vivo secretion of vWF in SHR and WKY rats but not cultured cerebrovascular EC indicates that observed elevations in plasma vWF were not derived from cerebrovascular EC. lt is suggested that hypertension may function as a risk factor for thrombotic stroke by influencing factors involved in coagulation processes, such as vWF and factor VIII : c.}, subject = {Neurobiologie}, language = {en} } @techreport{WangSirenLiuetal.1994, author = {Wang, X. and Sir{\´e}n, Anna-Leena and Liu, Y. and Yue, T-L. and Barone, F. C. and Feuerstein, G. Z.}, title = {Upregulation of intercellular adhesion molecule-1 (ICAM-1) on brain microvascular endothelial cells in rat ischemic cortex [Research Report]}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62952}, year = {1994}, abstract = {The expression of intercellular adhesion molecule 1 (ICAM-1) was studied in rat focal ischemic cortex. A significant increase in ICAM-1 mRNA expression in the ischemic cortex over Ievels in contralateral (nonischemic) site was observed by means of Northern blot analysis following either permanent or temporary occlusion with reperfusion of the middle cerebral artery (PMCAO or MCAO with reperfusion) in spontaneously hypertensive rats. In the ischemic cortex, Ievels of ICAM-1 mRNA increased significantly at 3 h (2.6-fold, n = 3, P < 0.05), peaked at 6 to 12 h (6.0-fold, P < 0.01) and remained elevated up to 5 days (2.5-fold, P < 0.05) after PMCAO. The profile of ICAM-1 mRNA expression in the ischemic cortex following MCAO with reperfusion was similar to that following PMCAO, except that ICAM-1 mRNA was significantly increased as early as 1 h (6.3-fold, n = 3, P < 0.05) and then gradually reached a peak at 12 h (12-fold, P < 0.01) after reperfusion. ICAM-1 mRNA expression in ischemic cortex following PMCAO was significantly greater in hypertensive rats than in two normotensive rat strains. Immunostaining using anti-ICAM-1 antiborlies indicated that upregulated ICAM-1 expressionwas localized to endotheIial cells of intraparenchymal blood vessels in the ischemic but not contralateral cortex. The data suggest that an upregulation of ICAM-1 mRNA and protein on brain capillary endothelium may play an important rote in leukocyte migration into ischemic brain tissue.}, subject = {Neurobiologie}, language = {en} }