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  • 1
    ISSN: 1432-0738
    Keywords: Atropine ; Cardiac output ; Cholinesterase inhibitors ; Pralidoxime compounds ; Respiration ; Peripheral vascular resistance ; Atmung ; Atropin ; Cholinesterase-Gifte ; Herzzeitvolumen ; Peripherer Gefäßwiderstand ; Pralidoxim-Verbindungen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 53 Katzen in Chloralose-Urethan-Narkose wurde durch intravenöse Infusion von 1,2 mg/kg Paraoxon (0,02 mg/kg×min) eine Organophosphatvergiftung ausgelöst. Während der Vergiftung und nach erfolgreicher Behandlung mit esterasereaktivierenden Oximen (Pralidoxim, Obidoxim) und Atropin wurden Blutdruck, Herzzeitvolumen, periphere Durchblutung sowie pH, pCO2 und pO2 im arteriellen Blut über einen Zeitraum von 7 Std verfolgt. Dabei ergab sich: 1. Während der Vergiftung bildete sich eine Blutdrucksenkung und Herzzeit-volumenabnahme aus, die durch Methylatropin, das nur die peripheren muscarinartigen Vergiftungserscheinungen zu antagonisieren vermag, auch bei künstlicher Atmung nicht beseitigt werden konnte. 2. Nach intravenöser Zufuhr von Pralidoxim (30,0 mg/kg) oder Obidoxim (15,0 mg/kg) i. v. verschwanden innerhalb weniger Minuten alle peripheren Vergiftungssymptome. 3. Bei allen behandelten Tieren bildete sich innerhalb von 30–60 min eine anhaltende Erhöhung des peripheren Gefäßwiderstandes aus, der auch durch hohe Dosen von Atropin (bis 5,0 mg/kg) nicht zu beseitigen war. 4. Nach alleiniger Behandlung der Paraoxonvergiftung mit Pralidoxim kam es zu einer zentralen Atmungsstimulation, die zur respiratorischen Alkalose führte. Diese Auswirkung der Hirn-AChE-Vergiftung konnte durch Atropin beseitigt werden. Nach Behandlung der Paraoxonvergiftung mit Obidoxim wurde eine derartige Atmungsstimulation nicht beobachtet. Aus den experimentellen Befunden ergeben sich einige Anhaltspunkte für mögliche Spätkomplikationen bei erfolgreicher Behandlung von Organophosphat-vergiftungen mit esterasereaktivierenden Oximen und Atropin.
    Notes: Summary Organophosphate poisoning was induced in 53 cats under urethanechloralose anesthesia by intravenous infusion of 1.2 mg/kg (0.02 mg/kg/min) paraoxone. Arterial blood pressure, cardiac output, peripheral blood flow, as well as arterial pH, pO2 and pCO2 were monitored over a period of seven hours during the intoxication and successful treatment with cholinesterase reactivating oximes (pralidoxime and obidoxime). The results are summarized as follows: 1. There was a fall in blood pressure and cardiac output with the progress of intoxication which was not alleviated by either methylatropine (capable of antagonizing only peripheral muscarine-like intoxication signs and symptoms) or by mechanical support of respiration. 2. The peripheral signs of intoxication disappeared within minutes upon intravenous injection of pralidoxime (30.0 mg/kg) or obidoxime (15.0 mg/kg). 3. There was a persistant elevation of peripheral vascular resistance in all animals treated which developed within 30–60 minutes and could not be influenced by high doses of atropine (up to 5.0 mg/kg). 4. Following the treatment of paraoxone poisoning with pralidoxime alone, there resulted a central respiratory stimulation which led to actual respiratory alkalosis. This effect of inhibition of the acetylcholine esterase in the brain could be abolished by atropine. When the paraoxone intoxication was treated with obidoxime alone, no comparable stimulation of respiration was observed. The results of these experiments point to some possible late complications by the successful treatment of organophosphate poisoning with cholinesterase reactivating oximes and atropine.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 30 (1973), S. 161-174 
    ISSN: 1432-0738
    Keywords: Atropine ; N-Methylatropine ; Phrenic Nerve ; Respiration ; Atmung ; Atropin ; N-Methylatropin ; N. phrenicus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 78 narkotisierten, bivagotomierten Ratten wurde die Entladungsfrequenz inspirationsaktiver Einzelfasern vom N. phrenicus unter der Einwirkung von Atropin untersucht. Dabei ergab sich: 1. Atropin führte in Dosen von 0,6; 1,2; 2,4 und 4,8 mg/kg i.v. zu einer dosisabhängigen Verlängerung der Impulsabstände und zu einer Abnahme der Spikezahlen in inspirationsaktiven Phrenicus-Motoneuronen. Die Atmungsfrequenz war demgegenüber nach Atropin gesteigert. 2. Bei Stimulation der Atmung durch Anoxie (12 Vol.- % O2) oder Hypercapnie (5 Vol.- % CO2) war die erreichbare Steigerung der Entladungsfrequenz und die Erhöhung der Spikezahlen nach Atropin (1,0 mg/kg) absolut eingeschränkt, die relativen Änderungen waren iedoch in beiden Fällen vor und nach Atropinbehandlung gleich. 3. N-Methylatropin(1,0 mg/kg)zeigte keine Wirkung auf die Entladungsfrequenz im N. phrenicus. 4. Nach Denervation des Carotissinus war die Reaktion auf Atropin unverändert. Die unterschiedliche Wirkung von Atropin auf die Atmungstiefe (Zunahme der Impulsabstände, Abnahme der Spikezahlen) und auf die Atmungsfrequenz (Steigerung der Atmungscyclen pro Zeiteinheit) scheint nicht durch eine Beeinflussung der Chemoreception, sondern durch eine direkte Wirkung an der zentralen Atmungsteuerung zustandezukommen.
    Notes: Abstract The effect of atropine on discharge pattern of phrenic motoneurons was investigated in rats after vagotomy. The following results were obtained: 1. Atropine increased the distance of impulses, while the number of spikes was reduced. This effect was dose dependent for 0.6, 1.2, 2.4, and 4.8 mg/kg atropine injected intravenously. At the same time the frequency of respiration increased after administration of atropine. 2. Following atropine the effect of O2-deficiency (12 Vol.-%O2) or CO2-excess (5 Vol.-% CO2 on frequency of impulses and number of spikes was absolutely reduced, but both reactions were relatively unchanged. 3. N-Methylatropine did not influence the discharge pattern in phrenic motoneurons. 4. The effect of atropine on frequency of impulses was also demonstrable after denervation of carotid sinus. The different effect of atropine on depth of respiration (increase in the distance of impulses, reduction of spike number) and respiratory frequency is not elicited by alteration of chemoreception. The results indicate that atropine effects the discharge pattern of phrenic motoneurons by direct action on central respiratory regulation.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1912
    Keywords: Key words 5-Hydroxytryptamine (5-HT ; serotonin) ; 5-HT1D receptors ; 5-HT1Dβ receptors ; Endothelial cells ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Pharmacological evidence has suggested the presence of 5-hydroxytryptamine (5-HT, serotonin), 5-HT1D receptors on endothelial cells but these receptors have never been identified unambiguously on this type of cells. We now report that human umbilical vein endothelial cells (HUVEC) express 5-HT1D receptors coupled to inhibition of cyclic AMP formation. 5-HT and the 5-HT1D receptor agonists 5-carboxamidotryptamine (5-CT) and sumatriptan were approximately equipotent at inhibiting forskolin-stimulated cyclic AMP accumulation in HUVEC (mean pEC50 7.6–8.2, maximal effect 30% inhibition). The 5-HT1A receptor agonist, 8-OH-DPAT was clearly less potent (pEC50 6.2) and less efficacious. The selective 5-HT1D receptor antagonist, GR127935 (1 nM) markedly inhibited the effect of 5-HT (apparent pKB 10.8). Reverse transcription-polymerase chain reaction analysis showed the mRNA for 5-HT1Dβ receptors to be expressed in HUVEC. These results demonstrate the presence of functional 5-HT1D receptors and the expression of 5-HT1Dβ receptor mRNA in HUVEC. They support the involvement of 5-HT1Dβ receptors in endothelial-mediated responses to 5-HT.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1912
    Keywords: 5-Hydroxytryptamine (5-HT, serotonin) ; 5-HT1D receptors ; 5-HT1Dβ receptors ; Endothelial cells ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Pharmacological evidence has suggested the presence of 5-hydroxytryptamine (5-HT, serotonin), 5-HT1D receptors on endothelial cells but these receptors have never been identified unamiguously on this type of cells. We now report that human umbilical vein endothelial cells (HUVEC) express 5-HT1D receptors coupled to inhibitiion of cyclic AMP formatin. 5-HT and the 5-HT1D receptor agaonists 5-carboxamidotryptamine (5-CT) and sumatriptan were approximately equipotent at inhibiting forskolin-stimulated cyclic AMP accumulation in HUVEC (mean pEC50 7.6–8.2, maximal effect 30% inhibition). The 5-HT1A receptor agonist, 8-OH-DPAT was clearly less potent (pEC50 6.2) and less efficacious. The selective 5-HT1D receptor antagonist, GR127935 (1 nM) markedly inhibited the effct pf 5-HT (apparent pKB 10.8). Reverse transcription-polymerase chain reaction analysis showed the mRNA for 5-HT1Dβ receptors to be expressed in HUVEC. These results demonstrate the presence of functional 5-HT1D receptors and the expression of 5-HT1Dβreceptor mRNA in HUVEC. They support he involvement of 5-HT1Dβ receptors in endothelial-mediated responses to 5-HT.
    Type of Medium: Electronic Resource
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