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  • 1
    Electronic Resource
    Electronic Resource
    The Structure of Sleep is Related to the Learning Ability of Rats (1993)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 5 (1993), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Using electroencephalographic methods, rats learning or not learning a two-way active avoidance task were found to differ significantly in the structure of sleep determined the day before training. The main differences concerned (i) synchronized sleep episodes followed by wakefulness, which were longer and fewer in learning rats; (ii) paradoxical sleep episodes, which were longer in learning rats. Significant correlations were present between the number and/or the average duration of synchronized sleep episodes followed by wakefulness or by paradoxical sleep and the number of avoidances or escapes scored in the training session. Power spectral analysis indicated that the relative output in the 6 – 7-Hz region was higher in learning rats, notably during short episodes of synchronized sleep followed by paradoxical sleep. As two-way active avoidance training induces comparable modifications in postacquisition sleep (Ambrosini et al., Physiol. Behav., 51, 217 – 226, 1992), the features of preacquisition sleep which prevail in learning rats might directly determine their capacity to learn. Alternatively, they might reflect the existence of a genetic determinant independently conditioning the ability to learn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1993.tb00493.x
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  • 2
    Electronic Resource
    Electronic Resource
    Response variability to ischemic injury in the Mongolian gerbil: an electroencephalographic and behavioral study (1996)
    Springer
    Neurological sciences 17 (1996), S. 219-225 
    Details
    ISSN: 1590-3478
    Keywords: Gerbil ; Transitional ischemia ; EEG power spectra ; Passive avoidance training ; Ischemic tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario Gli effetti precoci di un'ischemia cerebrale globale di 5 o 10 min, della manipolazione chirurgica e dell'anestesia con alotano sono stati valutati nel gerbillo della Mongolia per mezzo dell'esame elettroencefalografico (EEG) e neurologico e dell'addestramento all'evitamento passivo. I gerbilli “sensibili all'ischemia” (rispettivamente il 33% e 64% degli ischemici per 5 e 10 min) morirono durante la chiusura di entrambe le carotidi comuni o entro le 24 ore successive. Gli animali “resistenti all'ischemia” risposero in modo variabile al trattamento. A 6 ore dall'ischemia, tutti gli animali presentavano un'attività EEG caratterizzata da un aumento dell'attività delta (1–4 Hz) e da una diminuzione della banda theta2 (6–9 Hz) che a 24 ore tendevano a normalizzarsi. Deficit di apprendimento fu osservato in 5 gerbilli ischemici 5 min (83%), in 1 controllo-sham 5 min (17%) e in 1 anestetizzato con alotano (17%). Quattordici giorni dopo l'ischemia il danno istologico fu rilevato in 4 gerbilli ischemici ed in 1 controllo sham 5 min. Nell'insieme, questo studio conferma la variabile sensibilità dei gerbilli all'ischemia cerebrale. Inoltre, sebbene i diversi effetti della chiusura delle carotidi siano stati attribuiti alla variabilità del sistema cerebrovascolare, i nostri dati suggeriscono che anche meccanismi cellulari endogeni potrebbero proteggere dall'ischemia. Per questo motivo, sarebbe utile indagare sulle cause molecolari della variabile tolleranza ischemica mostrata dal gerbillo.
    Notes: Abstract The early effects of 5 or 10 min global cerebral ischemia, sham operation and halothane anesthesia were evaluated in Mongolian gerbils by means of electroencephalography (EEG), neurological examination and passive avoidance training. The “ischemia-sensitive” gerbils (33% and 64% of the 5 and 10 min ischemic groups, respectively) died during carotid ligation or within 24 h; the “ischemia-resistant” gerbils showed variable behavioral responses. Six hours after ischemia, all of the animals presented EEG activity characterized by increased delta (1–4 Hz) activity and a decreased theta2 (6–9 Hz) band, with a tendency to recovery at 24 h. Learning impairment was observed in 5 of the 5 min ischemic animals (83%) and in 1 sham (17%) and 1 halothane (17%) control. Fourteen days after ischemia, histologic damage was observed in 4 ischemic gerbils and 1 sham control. On the whole, this study confirms the widely variable susceptibility of gerbils to cerebra ischemia. Moreover, although the variable effects of carotid occlusion have been attributed to multiple factors involving the cerebrovascular system, our data suggest that endogenous cellular mechanisms might protect against ischemia. In view of this consideration, it would be useful to investigate the molecular causes of the variable cerebral ischemic tolerance shown by Mongolian gerbils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01995687
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  • 3
    Electronic Resource
    Electronic Resource
    Variable response of the Mongolian gerbil to unilateral carotid occlusion: Magnetic resonance imaging and neuropathological characterization (1995)
    Springer
    Neurological sciences 16 (1995), S. 517-526 
    Details
    ISSN: 1590-3478
    Keywords: Mongolian gerbil ; Hemispheric ischemia ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario Nella presente ricerca abbiamo valutato nel gerbillo della Mongolia l'evoluzione e la gravità del danno ischemico dopo chiusura permanente di una delle arterie carotidi comuni (ACC) mediante RM convenzionale (RM con immagini pesate in T2) e analisis istologica. Subito dopo la chiusura di una ACC, gli animali hanno presentato una differente sintomatologia clinica. La mortalità (46%) rilevata entro le prime 48 ore è stata considerata un indice di “sensibilità allostroke”. Gli animali “resistenti allostroke” hanno mostrato un'ampia variabilità sia nell'evoluzione che nella gravità del danno ischemico. L'iperintensità del segnale e la negatività all'esame RM osservate entro 30 ore dalla legatura della ACC non sempre correlavano con il danno istologico cerebrale rilevato a 14 giorni. Una stretta correlazione è stata stabilita tra le immagini pesate in T2 e ottenute dopo 30 ore dalla occlusione della ACC e la neuropatologia. Infatti, i gerbilli negativi alla RM non presentavano lesioni, mentre un'alterazione di segnale era sempre predittiva di danno ischemico. Inoltre l'esame RM tardivo ha evidenziato dilatazione ventricolare. L'istopatologia ha dimostrato che il danno ischemico differiva tra i gerbilli “resistenti allo stroke” e spesso era bilaterale. Questo studio conferma la diversa suscettibilità all'infarto emisferico dopo chiusura permanente di una ACC e suggerisce che la RM convenzionale potrebbe essere un metodo non invasivo utile per 1) identificare e/o selezionare gli animali inclini a maturare danno ischemico e 2) monitorare l'efficacia di un trattamento terapeutico senza sacrificare gli animali.
    Notes: Abstract In the present investigation, we estimated both the evolution and the severity of ischemic damage following unilateral carotid occlusion (UCO) in Mongolian gerbils by using conventional magnetic resonance imaging (MRI, i.e. T2 weighted imaging) and histological techniques. Immediately after UCO, the animals showed different clinical effects. The mortality (46%) detected within the first 48h was considered an “stroke-sensitivity”; the “stroke-resistant” animals showed wide variability in terms of both temporal evolution and the extent of ischemic damage. The signal hyperintensity and negative MRI observed during the first 30h after UCO did not always correlate with the cerebral damage presented after 14 days, although a close correlation was established between the T2 weighted images taken more than 30h after UCO and neuropathology: the gerbils negative to imaging showed no morphological changes, whereas an enhanced signal was always prognostic of ischemic injury. Moreover, late MRI documented ventricular dilatation. Histopathology showed that the ischemic damage differed among the stroke-resistant gerbils and was often bilateral. The present study confirms the differences in gerbil susceptibility to hemispheric infarction after permanent UCO and suggests that conventional MRI may be a useful non-invasive method for i) identifying the stroke-resistant animals prone to mature ischemic injury and ii) monitoring the evolution of therapeutic efficacy without sacrificing animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02282909
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  • 4
    Electronic Resource
    Electronic Resource
    Differential changes in Cu, Zn and Mn superoxide dismutase activity in developing rat brain and liver (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 753-755 
    Details
    ISSN: 1420-9071
    Keywords: Prenatal and postnatal development ; Cu, Zn and Mn superoxide dismutase ; free radicals ; aging ; differentiaiton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The aim of our study was to assess the pattern of copper and zinc-containing superoxide dismutase (Cu, ZnSOD) and manganese-containing superoxide dismutase (MnSOD) activity from embryonic life to senescence in rat brain and liver. The two isoenzymes showed different profiles in the two organs examined. In particular, the cerebral MnSOD activity profile suggests a primary role during differentiation of this enzymatic form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01939957
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