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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 62 (1984), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Propionylcholine, a novel analogue of acetylcholine, was identified in green plants by gas chromatography/mass spectrometry. Propionylcholine was found in the leaves of the following species previously shown to contain acetylcholine and cholinesterase activity: Codiaeum variegatum Blume, Phaseolus aureus Roxb. cv. Berken, Plantago rugelli Decne., Populus grandidentata Michx., and Betula pendula Roth. The quantities of propionylcholine ranged from a high of 2.3 nmol (g fresh weight)−1 in C. variegatum to a low of 0.11 nmol (g fresh weight)−1 in P. rugelli. These amounts represented 6 to 8% of the levels of acetylcholine. In contrast to animal tissues which rarely synthesize propionylcholine, this compound was found in all species examined which represented five families of flowering plants.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 61 (1984), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Acetylcholine in plants was identified by gas chromatography/mass spectrometry. Acetylcholine was found in the following species from 13 families: Betula pendula, Codiaeum variegatum, Ilex opaca, Liquidambar styraciflua, Lonicera japonica, Phaseolus aureus, Phaseolus vulgaris, Pisum sativum, Plantago rugelli, Populus grandidentata, Prunus serotina, Rhus copallina, Smilax hispida, Viburnum dilatatum, and Zea mays. Levels of acetylcholine in leaves ranged from a low of 0.14 ± 0.05 (mean ± SEM) nmol (g fresh weight)−1 in I. opaca to a high of 53 ± 6.6 nmol (g fresh weight)−1 in P. aureus. Acetylcholine was found in all tissues examined regardless of the organ (leaves, stems, or roots) or developmental stage (seedlings, mature plants, or seeds). For P. aureus, continuous light exposure increased acetylcholine levels of leaves, and decreased levels in stem when compared to dark controls. Levels of choline, a precursor of acetylcholine, found in leaves ranged from a low of 84 ± 7.0 nmol (g fresh weight)−1 in L. styraciflua to a high of 3700 ± 200 nmol (g fresh weight)−1 in P. aureus. With these findings, three out of the four components of the cholinergic system have now been identified in plants.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2072
    Keywords: Cholinergic function ; Acetylcholine ; Choline ; Levels ; Turnover rates ; Gas chromatography ; Lead poisoning ; Malnutrition ; Central nervous system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were exposed to lead acetate from birth, and were killed at the age of 44–51 days for analysis of levels and turnover rates of acetylcholine (ACh). Steady-state levels of ACh were not altered in midbrain, cortex, hippocampus, or striatum of lead-exposed rats. Similarly, no changes in choline (Ch) concentrations were found in cortex, hippocampus, or striatum. In the midbrain, however, a 30% reduction in Ch levels was observed. Changes in specific activity of Ch and ACh were measured as a function of time in selected brain areas of rats infused with a radio-labeled precursor of Ch. Specific activities of ACh were not altered. Ch specific activities were, however, significantly elevated in all brain areas examined, as compared with age-matched control rats. The in vivo ACh turnover rate in cortex, hippocampus, midbrain, and striatum was diminished by 35%, 54%, 51% and 33%, respectively. These findings provide direct evidence for an inhibitory effect of lead exposure from birth on central cholinergic function in vivo. Since a significant reduction of body weight was found in those animals treated with lead acetate, the alteration of central cholinergic function may partially be attributed to malnutrition observed in the lead-exposed animals.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 78 (1982), S. 170-175 
    ISSN: 1432-2072
    Keywords: Acetylcholine ; Choline ; Soman ; Organophosphate ; Anticholinesterase ; Toxicity ; Lethality ; CNS ; Brain areas ; Rats ; Gas chromatography ; Mass spectrometry ; Time course ; Cholinergic function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The time course of changes in rat brain levels of acetylcholine (ACh) and choline (Ch) was investigated following a single SC injection of soman (0.9 LD50, 120 μg/kg) to understand the relationship between central neurotransmitter alteration and soman toxicity. Of the animals exposed to the dose of soman, 46% died within 24 h, with maximum mortality occurring during the first 40 min following soman administration. In a second group, surviving rats were killed at various times after treatment by a beam of focused microwave radiation to the head, and ACh and Ch levels were determined by gas chromatography-mass spectrometry. Soman produced a maximal ACh elevation in the brain stem at 20 min (34.4%), in cerebellum at 40 min (51.9%), in cortex and striatum at 2 h (320.3% and 35.2%, respectively), and in hippocampus and midbrain at 3 h (94.5% and 56.8%, respectively). ACh levels remained above normal approximately 30 min in the brain stem; 2 h in the midbrain, cerebellum, and striatum; 8 h in the cortex; and 16 h in the hippocampus. Ch levels were elevated in all areas except the striatum. Ch maxima occurred at 10–40 min and returned to control levels approximately 3 h after injection. Results suggest that perturbation of ACh levels due to soman was not uniform throughout the brain and that soman toxicity may reflect ACh changes in multiple areas, rather than changes in any given area. These data further suggest a possible relationship between elevated Ch levels and soman toxicity.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 84 (1984), S. 426-430 
    ISSN: 1432-2072
    Keywords: Physostigmine ; Antinociception ; Dexamethasone ; Endogenous opiates ; Adrenalectomy ; Tail flick ; Pituitary ; adrenal axis ; Muscarinic receptors ; Cholinesterase inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The tail-flick procedure was used to study the antinociceptive effects of physostigmine in adrenalectomized and sham-operated rats. At 5 days after surgery, they were tested 30 min after either 0.32 or 0.45 mg/kg IP physostigmine. Adrenalectomized animals showed significantly greater elevation of TF scores from predrug latencies than the sham controls at both doses of physostigmine. Following 3 days of dexamethasone replacement therapy on days 18, 19, and 20 post-surgery the antinociceptive effects of physostigmine were uniformly attenuated across doses or surgical groups. On the other hand, animals receiving saline injection instead of dexamethasone did not manifest any reduction of the physostigmine antinociceptive effect. The potentiation by adrenalectomy and the reduction following dexamethasone of the antinociceptive effects of physostigmine suggest that these effects may be mediated through hypothalamic-pituitary-adrenal mechanisms and are consistent with β-endorphin-induced sensitization of opiate or cholinergic receptors.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2072
    Keywords: Methylphenidate ; Lead toxicity ; Cholinergic and catecholaminergic effects ; Mesencephalic reticular formation ; CNS ; Hyperkinesis ; Supersensitivity ; Oxotremorine ; Nicotine ; Model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of methylphenidate (MPH) and the cholinergic agonists nicotine and oxotremorine were tested on the spontaneous multiple unit activity in the mesencephalic reticular formation of two groups of rats. In control rats i.v. MPH (1 mg/kg), nicotine (0.125 mg/kg), and oxotremorine (0.5 mg/kg) all attenuated the unit activity with latencies of less than 10 min. In another group of rats, exposed to lead acetate since birth, the extent of attenuation of unit activity induced by MPH and nicotine was reduced and the latency of effect was delayed by 45–50 min. The latency of the oxotremorine effect was not changed but the attenuation of unit activity was more pronounced in the lead-treated group. Pretreatment with spiroperidol, to inhibit the aminergic receptors, diminished the inhibitory effect of MPH in the control group but not in the lead-treated group, whereas the attenuating effect of oxotremorine was not affected in either group. These data support our previous evidence that MPH exerts its action in the central nervous system by a cholinergic pathway in addition to published catecholaminergic pathways. Furthermore, the present findings indicate that chronic leadexposure in rats results in cholinergic hypofunction and supersensitivity at central cholinergic receptor sites. This alteration of central cholinergic function may be partially attributed to the malnutrition observed in the lead-exposed animals.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2072
    Keywords: Methylphenidate ; Hyperkinesis ; Mesencephalic Reticular Formation ; Thalamus ; Attention ; Arousal ; CNS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intravenous administration of methylphenidate (1 or 2 mg/kg) markedly attenuated the unit discharge rate in the mesencephalic reticular formation of rats and cats. Concurrently this drug enhanced the neural activity in the primary sensory nuclei of the thalamus. The differential effects of methylphenidate on these two neural systems suggest a possible mechanism by which it may improve attentive processes in hyperkinesis.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 2 (1984), S. 237-242 
    ISSN: 0263-6484
    Keywords: Heart ; Feulgen-DNA ; Azure B-RNA ; microdensitometry ; soman toxicity ; cardiac muscle ; cytochemistry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myocardial nucleic acid responses were analysed in New Zealand White rabbits 20 min-1 h and 6-8 h following single subcutaneous injections of soman (20, 30, or 40 μg kg-1). Scanning-integrating microdensitometry was used to quantify Azure B-RNA and Feulgen-DNA (F-DNA) levels, and changes in the suseptibility of chromatin to Feulgen acid hydrolysis (F-DNA reactivity) of individual ventricular myocardial cells. With a dosage of 20 μg kg-1 soman, no RNA alterations were evidenced at 1 h whereas at 6-8 h myocardial cells exhibited higher RNA levels and an increase in F-DNA reactivity of chromatin. With dosages of 30 and 40 μg kg-1 soman there was an augmentation in RNA levels and in the acid hydrolysability of nuclear chromatin at both 20 min-1 h and 6-8 h. It is postulated that the observed cellular transformations represent a compensatory augmentation in myocardial metabolic functioning presumably in response to an increased functional demand on the ventricular myocardium. The absence of cytopathic or cytochemical evidence of impairment in nucleic acid metabolism is inconsistent with the premise that soman exerts direct cytotoxic effects on rabbit myocardium.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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