TY - JOUR A1 - Karppanen, H. A1 - Sirén, Anna-Leena A1 - Eskeli-Kaivosoja, Alice T1 - Central cardiovascular and thermal effects of Prostaglandin F2α in rats N2 - Administration of PGF 2IX (0.2-6.4 J.lg) into the lateral cerebral ventricle (i.c.v.) induced dosedependent increases in blood pressure , heart rate and body temperature in urethane-anaesthetised rats, but had no effect on these parameters when the same dose range was administered intravenously. Peripheral pretreatment with sodium meclofenamate (50 mg/kg s.c.) sltifted all the dose-response curves for PGF 2IX (i.c.v.) to the left, but indomethacin (50 mg/kg s.c.) did not significantly affect those changes. Central pretreatment with sodiurn meclofenamate or indomethacin (1.25 mg per rat i.c.v.) failed to modify significantly the effects of centrally administered PGF 2IX' The results support previous suggestions that PGF 2IX may participate in the central control of the cardiovascular and thermoregulatory systems, and also suggest that there may be differences in the sites and/or modes of action between sodiurn meclofenamate and indomethacin. KW - Prostaglandine Y1 - 1979 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47955 ER - TY - JOUR A1 - Sirén, Anna-Leena A1 - Karppanen, H. T1 - Influence of analgesic antipyretics on the central cardiovascular effects of clonidine in rats N2 - No abstract available KW - Prostaglandine Y1 - 1980 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-48640 ER - TY - JOUR A1 - Sirén, Anna-Leena T1 - Central cardiovascular and thermal effects of prostacyclin in rats N2 - Prostacyclin (PGI2) induced a dose-dependent decrease in blood pressure with slight increases in heart rate and body temperature, when administered at the doses of 0.1-100 ~g into the lateral cerebral ventricle (i.c.v.) of the urethane-anaesthetised rat. When the same doses were administered intravenously, both the blood pressure and heart rate decreased. Central pretreatment wib~ sodiurn meclofenamate (1 mg/rat i.c.v.) antagonised the central hypotensive effect of PGI2 but i.c.v. pretreatrnent of the rats with indomethacin (1 mg/rat) failed to affect the PGI 2-induced hypotension. Central pretreatment with two histamine H2-receptor antagonists, cimetidine (500 ~g/rat i.c.v.) or metiamide (488 ~g/rat i.c.v.), antagonised the blood pressure lowering effect of 0.1 ~g dose of PGI2 but failed to affect the hypotension induced by higher PGI2 doses. Therefore the main central hypotensive effect of PGI2 seems not to be associated with the stimulation of histamine H2 -receptors in the brain. The hypotensive effect of i.c.v. administered PGI2 appears to be due to an action upon the central nervous system rather than to a leakage into the peripheral circulation. This assurnption is supported by the fact that sodiurn meclofenamate i.c.v. antagonised the effect of PGI 2. In addition, the chronotropic response to i.c.v. PGI2 was opposite to that induced by intravenous administration. The results also suggest that there may be differences in the mode of action between sodiurn meclofenamate and indomethacin. KW - Prostaglandine Y1 - 1981 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47943 ER - TY - JOUR A1 - Sirén, Anna-Leena T1 - Differences in central actions of arachidonic acid and prostaglandin F\(_{2\alpha}\) between spontaneously hypertensive and normotensive rats N2 - Prostag1andin F\(_{2\alpha}\) (PGF\(_{2\alpha}\)) is one of the most common metabo1ites of arachidonic acid (M) in rat brain. When administered intracerebroventricularly (i.c.v.) to rats, both AA and PGFal exert dose-related hypertensive, tachycardic and hyperthermic effects. Metabolie alterations in the endogenaus formation of some prostaglandins in the brain-stem of spontaneously hypertensive rats (SHR) have been reported. Therefore the central effects of AA and PGF \(_{2\alpha}\) on blood pressure, heart rate and body temperature were studied both in SHR and nonootensive Wistar rats (NR) under urethane-anaesthesia. The hypertensive effect of AA i.c.v. (0.01-100 \(\mu\)g/rat) was larger in magni tude in SHR than in NR, but there was no significant difference in the M-induced changes of heart rate and body temperature between the groups. Pretreatment of NR wi th soditm1 :meclofenamate (1 mg/rat i.c.v.) antagonised the central effects of M indicating that these effects are not due to M itself but to its conversion to prostaglandins. Unlike the effects of AA, the central hypertensive, tachycardic and hyperthennic responses to PGF\(_{2\alpha}\) (0.5-50 l-lg/rat i.c.v .) were significantly attenuated in SHR. The present results obtained with M are conpatible with the previous assumption that the synthesis of prostaglandins in the brain of SHR might differ from that in NR. The results also demonstrate that the central effects of PGF\(_{2\alpha}\) are reduced in SHR. KW - Neurobiologie Y1 - 1982 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63324 ER - TY - JOUR A1 - Sirén, Anna-Leena T1 - Central cardiovascular and thermal effects of Prostaglandin E2 in rats N2 - Prostaglandin E2 (PGE2) increased the blood pressure, heart rate and body temperature, when administered at the doses ofO.OOI-IO,ug into the lateral cerebral ventricle (i.c.v.) of the urethane-anesthetised rat. The highest dose of 10 ,ug/rat induced a strong initial hypotensive effect. lntravenously (i.v.), PGE2 at the doses of 0.01-10 ,ug/rat caused a biphasic blood pressure response with dose-related initial decreases followed by slight increases in blood pressure. The heart rate and body temperature were slightly increased by i.v. administrations of PGE2 . The highest i.v. dose of 10 ,ug/rat initially decreased also the heart rate. Central pretreatment with indomethacin ( I mg/rat i.c.v.) partly antagonised all of the recorded central effects of PGE2 , while sodium meclofenamate (I mg/rat i.c. v.) abolished the hypertensive response to i.c. v. administered PGE2 but failed to significantly affect the PGE2-induced rises of heart rate and body temperature. The results support the previous suggestions that PGE2 may participate in the central cardiovascular and thermoregulatory contro!. The results also suggest that indomethacin and sodium meclofenamate antagonize the effects of exogenous prostaglandins. Since sodium meclofenamate, unlike indomethacin, affected preferentially the hypertensive response to centrally administered PGE2 , there may be differences in the sites and/or modes of action between these drugs. KW - Physiologie Y1 - 1982 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47960 ER - TY - JOUR A1 - Sirén, Anna-Leena T1 - Central cardiovascular and thermal effects of prostaglandin D2 in rats N2 - Prostaglandin D2 (PGD2) is the most common prostaglandin type of tile rat brain. Recently a neurornodulator role for PGD2 has been suggested. In the present work the central cardiovascular and thermal effects of PGDz were studied in urethane-anaesthetised rats. Mlen adrndnistered at the doses of 0.001-10 ~g/rat into the lateral cerebral ventricle(i.c.v.), PGD2 slightly increased the blood pressure, heart rate and body ternpera~ ure. The highest dose caused also an initial hypotensive effect. Upon lntravenous injections PGD2 (0.1-10 ~g/rat) initially decreased and then weakly increased the blood pressure but had only negligible effects on heart rate and body temperature. Central pretreatment with sodium meclofenamate or indomethacin (1 mg/rat i.c.v.) antagonised effectively all the recorded central effects of PGD2. The central cardiovascular and thermal effects of PGD2 were much weaker than those obtained earlier with other prostaglandins, such as PGF2alpha and PGE2.. Therefore, in spite of its abundance in the brain PGD2 may not be very important for the central cardiovascular and thermal regulation in the rat. KW - Medizin Y1 - 1982 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-48658 ER - TY - JOUR A1 - Sirén, Anna-Leena A1 - Paakkari, I. T1 - Cardiovascular effects of TRH i.c.v. in conscious rats N2 - In addition to the endocrine effects, the thyrotropin releasing hormone (TRH) is known to induce dose-dependent increases in blood pressure and heart rate after intracerebroventricular (i.c.v.) administration in urethane-anaesthetised rats (1, 2). The a~ of the present study was to investigate whether TRH has similar effects in conscious rats of various strains i.e. spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto (WKY) and Wistar (NR) rats. KW - Medizin Y1 - 1984 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-49071 ER - TY - JOUR A1 - Sirén, Anna-Leena A1 - Svarström-Fraser, M. A1 - Paakkari, I. T1 - Central cardiovascular effects of the endoperoxide analogue U-46619 i.c.v. in rats N2 - Thromboxanes are abundantly present in the rat brain but their possible physiological functions in the brain are not known. The prostaglandin endoperoxide analogue U-46619 is a selective agonist of TxA2 receptors in many peripheral tissues. In the present study the ·central cardiovascular and ventilatory effects of U-46619 were investigated in rats. In conscious spontaneously hypertensive rats (SHR) U-46619 (1-100 nmol/kg i.c.v.) induced a strong dose-related increase in blood pressure but had no significant effect on heart rate. In conscious normotensive rats (NR) neither blood pressure nor heart rate was significantly affected. Furthermore, U-46619 (0.1-100 nmol/kg i.c.v.) had no significant effect on blood pressure, heart rate or ventilation in urethane-anaesthetised NR . The results demonstrate an increased sensitivity of SHR to TxA2. KW - Medizin Y1 - 1985 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-49064 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 - Paakkari, I. A1 - Nurminen, M-L. A1 - Sirén, Anna-Leena T1 - Cardioventilatory effects of TRH in anesthetized rats: role of the brainstem N2 - Cardioventilator responses were studied in anaesthetized rats after injections of TRH into either the lateral (i.c.v. lat) or the fourth (i.c.v. IV) cerebral ventricles. TRH induced a morerapid hypertensive effect i.c.v. IV than i.c.v. lat. Blocking of the cerebral aqueduct abolished the hypertensive and tachypnoeic effects of TRH i.c.v. lat but not those of TRH i.c.v. IV. It is concluded that TRH increased blood pressure and ventilation rate via brain stem structures close to the fourtli ventricle. KW - Neurobiologie KW - TRH KW - Cardiovascular KW - Ventilation KW - Brain stem Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63277 ER -