TY - JOUR A1 - Paakkari, P. A1 - Paakkari, I. A1 - Sirén, Anna-Leena A1 - Feuerstein, G. T1 - Respiratory and locomotor stimulation by low doses of dermorphin - a Mu\(_1\)-receptor mediated effect N2 - 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. KW - Neurobiologie Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63110 ER - TY - JOUR A1 - Hallenbeck, JM A1 - Dutka, AJ A1 - Kochanek, PM A1 - Sirén, Anna-Leena A1 - Pezeskpour, GH A1 - Feuerstein, G. T1 - Stroke risk factors prepare rat brainstem tissues for a modified localized Shwartzman reaction N2 - Stroke risk factors such as hypertension, diabetes, advanced age, and genetic predisposition to stroke were demonstrated to prepare rat brainstem tissues for a modified local Shwartzman reaction. A single intracisternal injection of endotoxin provoked the reaction, and affected rats manifested neurologie deficits accompanied by pathologie lesions. Brainstem infarcts developed in only a small proportion of rats without recognized risk factors after intracisternal injection of endotoxin. Thus, stroke risk factors, whieh are ordinarily regarded as operating through acceleration of atherosclerosis, may predispose to brain ischemia by local effects on brain mierocirculation such as those thought to underlie preparation of a tissue for the local Shwartzman reaction. KW - Gehirn KW - Durchblutung Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47971 ER - TY - JOUR A1 - Feuerstein, G. A1 - Zerbe, R. L. A1 - Sirén, Anna-Leena T1 - Supraoptic nuclei in vasopressin and hemodynamic responses to hemorrhage in rats N2 - 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. KW - Neurobiologie KW - Hypothalamus KW - Supraoptic nucleus KW - Hemorrhage KW - Vasopressin Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63057 ER - TY - JOUR A1 - Eimerl, J. A1 - Sirén, Anna-Leena A1 - Feuerstein, G. T1 - Systemic and regional hemodynamic effects of leukotrienes D\(_4\) and E\(_4\) in the conscious rat N2 - No abstract available KW - Neurobiologie Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63317 ER - TY - JOUR A1 - Feuerstein, G. A1 - Sirén, Anna-Leena A1 - Goldstein, DS A1 - Johnson, AK A1 - Zerbe, RL T1 - The effect of morphine on the hemodynamic and neuroendocrine responses to hemorrhagic shock in conscious rats N2 - We have previously reported that analgesic doses of morphine accelerate mortality of rats exposed to hemorrhage (Feuerstein and Siren: Circ Shock 19:293-300, 1986). To study the potential mechanisms involved in this phenomenon, rats were chronically implanted with catheters in the femoral vessels and morphine (1.5 or 5 mg/kg) was administered 30 min or 24 hr after bleeding (8.5 mll300 g over 5 min) while arterial blood pressure and heart rate were continuously monitored. Furthermore, the effect of morphine (5 mg/kg) on cardiac output (CO) response to hemorrhage was studied in rats chronically equipped with a mini thermistor for CO monitoring by a thermodilution technique. In addition, plasma catecholamines (HPLC), plasma renin activity (PRA, RIA), vasopressin (RIA), pH, and blood gases were also determined. Morphine administration 30 min after hemorrhage produced a pressor response and tachycardia which were in marked contrast to its depressor effect in intact rats. Morphine elevated PRA and epinephrine but not vasopressin, while blood pH and gases showed no consistent change as compared to salinetreated hemorrhaged rats. Morphine given after the bleeding resulted in enhanced cardiac depression in response to a second bleed of 2 m1l300 g. Our data suggest that activation of pressor mechanisms by morphine during hypovolemic hypotension might enhance vasoconstriction in essential organs, depress cardiac function, and further reduce effective tissue perfusion. KW - Medizin KW - hemorrhagic shock KW - opiates KW - catecholamlnes KW - renin KW - vasopressin Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-49033 ER - TY - JOUR A1 - Sirén, Anna-Leena A1 - Feuerstein, G. T1 - The Opioid System in circulatory control N2 - 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. KW - Neurobiologie Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63045 ER - TY - JOUR A1 - Sirén, Anna-Leena A1 - Powell, E. A1 - Feuerstein, G. T1 - Thyrotropin releasing hormone in hypovolemia: a hemodynamic evaluation in the rat N2 - ln the present study the effects of thyrotropin releasing hormone (TRH) and its stable analogue, CG3703, on cardiac output (thermodilution, Cardiomax) and regional blood flow (BF; directional pulsed Doppler technique) were investigated in hypovolemic hypotension in the rat. In urethan-anesthetized rats TRH (0.5 or 2 mg/ kg ia) or CG3703 (0.05 or 0.5 mg/kg ia) reversed the bleeding (27% of the blood volume)-induced decreases in mean arterial ... KW - Neurobiologie KW - cardiac output KW - total peripheral resistance KW - regional blood flow Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63288 ER - TY - JOUR A1 - Sirén, Anna-Leena A1 - Feuerstein, G. T1 - Thyrotropin releasing hormone-induced hindquarter vasodilation is mediated by \(\beta _2\)-adrenoceptors N2 - No abstract available KW - Neurobiologie Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63155 ER -