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  • 1
    Electronic Resource
    Electronic Resource
    Long term effects of septohippocampal lesions and intrahippocampal grafts on acetylcholine concentration, muscarinic stimulated formation of inositol phospholipids and electrically evoked release of neurotransmitters in the rat hippocampus (1991)
    Springer
    Experimental brain research 83 (1991), S. 633-642 
    Details
    ISSN: 1432-1106
    Keywords: Acetylcholine ; Fimbria/fornix ; Hippocampus ; Intracerebral grafts ; Muscarinic receptors ; Noradrenaline ; Phosphoinositides ; Serotonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Long Evans female rats sustained aspirative lesions of the septohippocampal pathways; subsequently, they received intrahippocampal suspension grafts of fetal septal-diagonal band or hippocampal tissue. The long term (8–10 months post-surgery) effects of these treatments were examined in the hippocampus for the following variables: concentration of hippocampal acetylcholine (ACh), muscarinic-stimulated (carbachol) formation of inositol monophosphate, accumulation of tritiated choline, noradrenaline (3H-NA) and serotonin (3H-5-HT), electrically evoked release of 3H-acetylcholine (3H-ACh), 3H-NA and 3H-5-HT, and choline acetyltransferase (ChAT) activity. The lesions decreased the levels of endogeneous ACh, the accumulation of 3H-choline and 3H-5-HT and the evoked release of both 3H-ACh and 3H-5-HT as well as the ChAT activity, but they failed to significantly affect the muscarinic-stimulated formation of inositol monophosphate and the accumulation and release of 3H-NA. Grafts of hippocampal cells were found to be ineffective on all lesion-induced effects. In contrast, grafts of septal-diagonal band origin attenuated the deficit of hippocampal concentrations of ACh and accumulation of 3H-choline without, however, improving release of 3H-ACh, accumulation and release of 3H-5-HT, and ChAT activity. These observations suggest that: (i) denervation-induced hippocampal muscarinic supersensitivity might not be long-lasting or the lesions, which in some cases spared the lateral edges of the fimbria, failed to induce any muscarinic supersensitivity, (ii) intrahippocampal grafts rich in cholinergic neurons do not foster recovery from the lesion-induced noncholinergic deficits we assessed, (iii) recovery of function may be expressed by some but not all biochemical or pharmacological cholinergic variables and (iv) graft-derived hippocampal reinnervation may be less efficient than the endogenous innervation of intact rats as indicated by the restoration of only some of the variables related to cholinergic function by intrahippocampal septal-diagonal band grafts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229841
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Time-dependent effects of intrahippocampal grafts in rats with fimbria-fornix lesions (1990)
    Springer
    Experimental brain research 81 (1990), S. 179-190 
    Details
    ISSN: 1432-1106
    Keywords: Acetylcholine ; Fimbria-fornix ; Hippocampus ; Locomotor activity ; Neural grafting ; Radial maze ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Based on three experiments, this study examined whether behavioral and histological effects of fetal septal or hippocampal grafts placed in the denervated hippocampus depend on the duration of post-grafting delays. Each experiment included four groups of rats: sham-operated rats (Sham), rats with aspirative lesions of the fimbria-fornix (Fifo) and rats given both Fifo lesions and intrahippocampal fetal suspension grafts of either septal (Fifo.ST) or hippocampal (Fifo.HT) origin. All rats were tested (i) for home cage activity, (ii) for activity and reactivity in an open field and (iii) for learning ability in a 8-arm radial maze. Except for home cage activity which was also monitored preoperatively, behavioral tests were conducted between 1–2 months postgrafting in Experiment 1 (EXP1), 5–6 months post-grafting in Experiment 2 (EXP2) and 10–11 months postgrafting in Experiment 3 (EXP3). Each test period lasted 3 weeks. Histological controls consisted of acetylcholinesterase (AChE) and cresyl violet staining. Graft size was estimated by computerized image analysis. Normal rats performed well in each experiment. In all experiments, rats with fimbria-fornix lesions showed increased activity in both their familiar (home cage) and unfamiliar (open field) environments, and their performances in the radial maze task were impaired. In no experiment did grafts, whether hippocampal or septal, affect “noncognitive” behavioral variables. However, maze performance was improved by hippocampal grafts in EXP1 (short delay) and by septal grafts in EXP2 (intermediate delay). No graft-induced effect was found in EXP3 (long delay). Concerning AChE-positivity in the dorsal hippocampus, fimbria-fornix lesions reduced staining densities by at least 60%. Both types of grafts were undiscernably AChE-positive, but only septal grafts provided the denervated hippocampus with a significant AChE-positive fiber ingrowth. Differences among groups in density of hippocampal AChE staining were comparable in all three experiments and no correlation between hippocampal AChE-positivity and maze performance was found. Our results suggest that graft-induced recovery from behavioral effects of fimbria-fornix lesions may depend on both the type of tissue implanted (hippocampal vs septal) and the post-grafting delay (1–2, 5–6 and 10–11 months). The recovery observed at a short post-grafting delay with hippocampal grafts and at a longer post-grafting delay with septal grafts was not persistent and concerned only cognitive function as assessed by radial maze performance. Regarding (i) the absence of any correlation between AChE staining and radial maze performance, and (ii) the lack of graft-derived AChE-positive fiber ingrowth in Fifo.HT rats with improved radial maze performance in EXP1, our results also suggest that factors other than graft-derived cholinergic fiber ingrowth might be involved in the graft-induced recovery observed in the radial maze.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230114
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Behavioural and neurochemical effects of superior cervical ganglionectomy in rats with septo-hippocampal lesions (1995)
    Springer
    Experimental brain research 102 (1995), S. 429-444 
    Details
    ISSN: 1432-1106
    Keywords: Fimbria-fornix lesion ; Hippocampus ; Radial-arm maze ; Spatial memory ; Sympathetic sprouting ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This longitudinal study, extending over 12 months, assessed the behavioural and biochemical effects of hippocampal sympathetic ingrowth (HSI) into the partially denervated hippocampus. Male Long-Evans rats received fimbria-fornix lesions (FIFO) or sham operations at 90 days of age. At the same time half of the rats from each group sustained bilateral ablation of the superior cervical ganglia (SCGX). A battery of behavioural tests, measuring spontaneous alternation, activity in the open field and home cage, and radial-maze performance, were employed, starting after one very short (16 days) and one extended (216 days) postoperative delay. Neurochemical analyses measuring choline acetyltransferase (ChAT) activity, high-affinity choline (HACU) and noradrenaline uptake by hippocampal synaptosomes (HANU), hippocampal noradrenaline ([NA]), serotonin ([5-HT]) and 5-hydroxyindoleacetic acid ([5-HIAA]) concentrations were carried out in a dorsal, a “middle” and a ventral region of the hippocampus. Lesion of the FIFO induced a significant and enduring deficit in radial-maze performance, in addition to a persistent locomotor hyperactivity. ChAT and HACU were significantly depleted in all three regions of the hippocampus at 12 months, and these deficits were negatively correlated with maze performance. SCGX in the presence of the FIFO lesion significantly reduced [NA] in the middle region of the hippocampus, as compared to SCGX rats, and contributed to a restoration of lesion-induced depletions in [5-HT] and [5-HIAA] in the middle and ventral hippocampal regions, whilst failing to elicit any behavioural changes at either time point. It is concluded that if lesion-induced HSI indeed occurred, as is suggested by neurochemical evidence, it had no effect upon the observed behavioural deficits elicited by transection of the FIFO in the rat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230648
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    Paper (German National Licenses)
    Fulltext
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