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  • 1
    Electronic Resource
    Electronic Resource
    Yohimbine facilitated acoustic startle in combat veterans with post-traumatic stress disorder (1995)
    Springer
    Psychopharmacology 117 (1995), S. 466-471 
    Details
    ISSN: 1432-2072
    Keywords: Yohimbine ; Noradrenergic ; Anxiety PTSD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Preclinical and clinical studies have suggested that the acoustic startle reflex (ASR) is a useful model to investigate the neurochemical basis of anxiety and fear states. This work has revealed that the anxiogenic alpha-2 receptor antagonist, yohimbine, increases the amplitude of the ASR in laboratory animals and in healthy human controls. Because of the growing body of data that support the hypothesis that severe stress results in substantial alterations in noradrenergic neuronal reactivity, the present investigation evaluated the effects of yohimbine on the ASR of 18 patients with PTSD and 11 healthy combat controls. Subjects received IV yohimbine (0.4 mg/kg) or saline placebo on 2 separate days in a randomized double blind placebo control design. A trial of two tone frequencies with varied intensity (90, 96, 102, 108, 114 dB) white noise and instantaneous rise time, was delivered binaurally through headphones. Tones were delivered every 25–60 s, for a 40-ms duration. Startle testing was performed 80 min post-infusion and lasted 15–20 min. Yohimbine significantly increased the amplitude, magnitude and probability of the ASR in combat veterans with PTSD, but did not do so in combat controls. Overall startle was significantly larger in the PTSD subjects; however, this did not account for the differential effect of yohimbine, since yohimbine had no significant effect in the control group. This study demonstrates an excitatory effect of yohimbine on the amplitude, magnitude and probability of the ASR in PTSD patients that is not seen in combat controls. In the context of the key role of this reflex in the alarm response, this finding adds to the array of documented behavioral, biochemical and cardiovascular effects of yohimbine in humans which support the relationship between increased noradrenergic function and exaggerated startle symptomatology of PTSD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246220
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Yohimbine — facilitated acoustic startle reflex in humans (1993)
    Springer
    Psychopharmacology 110 (1993), S. 342-346 
    Details
    ISSN: 1432-2072
    Keywords: Yohimbine ; Noradrenergic ; Anxiety
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Preclinical studies have suggested the acoustic startle reflex (ASR) may be a useful animal model to investigate the neurochemical basis of anxiety and fear states. This work has revealed that the anxiogenic alpha-2 receptor antagonist, yohimbine, increases the amplitude of the ASR in laboratory animals. The present investigation evaluated the effects of yohimbine on the ASR in healthy subjects. Seven healthy subjects received IV yohimbine (0.4 mg/kg) or saline placebo on two separate days in a randomized double blind placebo control design. A trial of 2 tone frequencies with varied intensity (90, 96, 102, 108, 114 dB) white noise, instantaneous rise time, was delivered binaurally through headphones. Tones were delivered every 25–60 sec, for a 30 ms duration. Startle testing was done 80 minutes post infusion and lasted 15–20 minutes. Sign rank testing indicated yohimbine caused an overall increase in startle amplitude, as well as significant augmentation of startle amplitude at 96, 102, 108, 114 decibels but not at the 90 dB intensity. Sign rank tests indicated a significant reduction of startle latency by yohimbine at only the 96 dB intensity. Significant correlations were observed between startle and peak anxiety, startle and plasma MHPG, peak anxiety and plasma MHPG. This study demonstrates in healthy human subjects an excitatory effect of yohimbine on the mangnitude of the ASR and a decrease in its latency. In the context of the key role of this reflex in the alarm response, this finding adds to the array of documented behavioral, biochemical and cardiovascular effects of yohimbine in humans which support the relationship between increased noradrenergic function and anxiety states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02251291
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Coordination of the cell-specific distribution of the four subunits of glycine decarboxylase and of serine hydroxymethyltransferase in leaves of C3-C4 intermediate species from different genera (1993)
    Springer
    Planta 190 (1993), S. 468-473 
    Details
    ISSN: 1432-2048
    Keywords: C3-C4 intermediate species (Flaveria, Moricandia, Panicum) ; C4 evolution ; Glycine decarboxylase (localization) ; Photorespiration ; Serine hydroxymethyltransferase (localization)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cell-specific distribution of the four subunit proteins (P, L, T and H) of glycine decarboxylase (GDC) and of serine hydroxymethyltransferase (SHMT) has been studied in the leaves of C3-C4 intermediate and C4 species of three genera (Flaveria, Moricandia and Panicum) using immunogold localization. Antibodies raised against these proteins from pea leaf mitochondria were used to probe Western blots of total leaf proteins of F. linearis Lag., M. arvensis (L.) DC and P. milioides Nees ex Trin. (C3-C4), and F. trinervia (Spring.) Mohr and P. miliaceum (L.) (C4). For all species, each antibody recognised specifically a protein of similar molecular weight to that in pea leaves. In leaves of M. arvensis the P protein was present in the mitochondria of the bundle-sheath cells but was undetectable in those of the mesophyll, whereas the L, T and H proteins and SHMT were present in both cell types. The density of immunogold labelling of SHMT on the mitochondria of mesophyll cells was less than that on those of the bundle-sheath cells, which correlates with the relative activities of SHMT in these cell types. These data reveal that the lack of functional GDC in the mesophyll cells of M. arvensis, which is the principal biochemical reason for reduced photorespiration in this species, is due to the loss of a single subunit protein. This lack of coordinate expression of the subunit proteins of GDC within a photosynthetic cell represents a clear difference between M. arvensis and other C3 and C3-C4 species. None of the GDC proteins was detectable in the mesophyll cells of the C3-C4 and C4 Flaveria and Panicum species but all were present in the bundle-sheath cells. The differences in the distribution of the GDC proteins in leaves of the C3-C4 species studied are discussed in relation to the evolution of photosynthetic mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224785
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Expression of the C3-C4 intermediate character in somatic hybrids between Brassica napus and the C3-C4 species Moricandia arvensis (1996)
    Springer
    Theoretical and applied genetics 93 (1996), S. 1234-1241 
    Details
    ISSN: 1432-2242
    Keywords: Brassica napus ; Moricandia arvensis ; Somatic hybridisation ; C3-C4 intermediate ; Photorespiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The wild crucifer Moricandia arvensis is a potential source of alien genes for the genetic improvement of related Brassica crops. In particular M. arvensis has a C3-C4 intermediate photosynthetic mechanism which results in enhanced recapture of photorespired CO2 and may increase plant water-use efficiency. In order to transfer this trait into Brassica napus, somatic hybridisations were made between leaf mesophyll protoplasts from cultured M. arvensis shoot tips and hypocotyl protoplasts from three Brassica napus cultivars, ‘Ariana’, ‘Cobra’ and ‘Westar’. A total of 23 plants were recovered from fusion experiments and established in the greenhouse. A wide range of chromosome numbers were observed among the regenerated plants, including some apparent mixoploids. Thirteen of the regenerated plants were identified as nuclear hybrids between B. napus and M. arvensis on the basis of isozyme analysis. The phenotypes of these hybrids were typically rather B. napus-like, but much variability was observed, including variation in flower colour, leaf shape and colour, leaf waxiness, fertility and plant vigour. CO2 compensation point measurements on the regenerated plants demonstrated that 3 of the hybrids express the M. arvensis C3-C4 intermediate character at the physiological level. Semi-thin sections through leaf tissues of these 3 plants revealed the presence of a Kranz-like leaf anatomy characteristic of M. arvensis but not found in B. napus. This is the first report of the expression of this potentially important agronomic trait, transferred from Moricandia, in M. arvensis x B. napus hybrids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223455
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    Paper (German National Licenses)
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