Biomedical subjects

F Amenta

Publications and source records attributed to F Amenta.

At least 307 records · Page 17Linked to original sources

PubMedDate not supplied

Reduced lipofuscin accumulation in senescent rat brain by long-term acetyl-L-carnitine treatment.

By using fluorescence microscopy and microfluorimetric techniques, the effects of ageing and of 11 months acetyl-L-carnitine (ALCAR) treatment on lipofuscin deposition within the cytoplasm of pyramidal neurons of rat prefrontal cortex and hippocampus (CA3 field) were assessed. No lipofuscin autofluorescence was observed in the nerve cell bodies of neurons under study in young rats (3 months of age), but lipopigment had accumulated in the same nerve cells of senescent rats (22 months of age). ALCAR administration significantly reduced the accumulation of lipofuscin within pyramidal neurons of the brain areas examined.

Acetylcarnitine↗

PubMedDate not supplied

Age-dependent nerve cell loss in the brain of Sprague-Dawley rats: effect of long term acetyl-L-carnitine treatment.

The age dependent loss of nerve cells was investigated in 22 brain areas from young (3 month), adult (13 month) and old (25 month) Sprague-Dawley rats. As in previous studies, we observed an age-related neuronal loss primarily in the archicortex and in the hippocampus and in other subcortical structures (amigdaloid nucleus, pontine nuclei, cerebellar cortex). In sensory areas of cerebral cortex the neuronal loss was less marked. The effect of a 6 month treatment with acetyl-L-carnitine (ALCAR) on the number of nerve cells in the same brain areas was also investigated. ALCAR treatment began when the rats were aged 16 months. ALCAR treatment was able to counteract the age-dependent decrease in nerve cell number primarily in the temporal and occipital cortical areas, in the archicortex and hippocampus. The above findings suggest that long term ALCAR treatment may be effective in slowing down the age-related nerve cell loss in some rat brain areas.

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Lactate dehydrogenase, succinate dehydrogenase and nucleotide tetrazolium reductase histochemical activities in the mesentric arteries and arterioles of young and old rats.

Age-related changes of the metabolic characteristics of large, medium and small brances of the rat superior mesenteric artery were investigated in young (4 month) and old (25 month) male Wistar rats, using enzyme histochemical techniques. The following enzymatic activities were examined: lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH); NADPH(2)-tetrazolium reductase (NADPHD) and NADH(2)-tetrazolium reductase (NADHD). The intensity of enzymatic reactions within the tunica media of the large, medium and small branches and within the tunica intima of the large and medium branches of the artery was assessed microphotometrically. In young rats the reactivity of enzymes investigated is similar in both the tunica media and the intima with the exception of SDH which reacts stronger in the media than in the intima. LDH and NADHD displayed the most intense reaction whereas SDH reaction was less intense. In old rats LDH and NADPHD reactivity decreased, SDH reactivity increased in the intima of large and medium branches; and SDH increased in the media of large branches. The possibility is discussed that an impaired endothelial function may represent one of the most consistent phenomena of aging of the superior mesenteric artery.

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Age-related changes of glutamate dehydrogenase in the rat hippocampus: an enzyme histochemical study.

Enzyme histochemical techniques associated with microphotometry were used to evaluate the reactivity of glutamate dehydrogenase (GDH) in the hippocampus of young (3 month) adult (12 month) and old (26 month) male Sprague-Dawley rats. In young rats the highest level of enzymatic reactivity was found in the stratum oriens of the CA-1-CA-4 fields followed in descending order by the molecular layer of fascia dentata, and by the layer of mossy fibers. In all the layers investigated GDH reactivity was higher in adult that in young rats. The older animals exhibited lower GDH reactivity than adult rats in almost all of the layers and higher enzymatic reactivity than in young rats in the stratum oriens of the CA-1-CA-4 fields. The hippocampus is known to be involved in the acquisition of two-way avoidance learning and is thought to utilize glutamate as one of its main neurotransmitters. These data suggest a possible relationship between hippocampal glutamatergic transmission and impairment of acquisition of avoidance learning occurring with age. Moreover, the possibility that a decreased glutamate catabolism occurring in old rats may contribute to the neuronal loss described in the hippocampus of aged rats is discussed.

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Changes of dopamine-sensitive cyclic AMP-generating system in the rat hippocampus as a function of age.

The dopamine (DA) D(1) and D(2) receptors coupled to the 3',5'-cyclic adenosine monophosphate (cAMP)-generating system were studied in membrane particles of the dorsal hippocampus in 3 (considered to be young), 12 (considered to be adult) and 24 (considered to be old) month male Sprague-Dawley rats. Activation of D(1) receptors with DA, apomorphine or SKF 82526 enhanced accumulation of cAMP in the hippocampus of rats of the three age groups examined. This stimulatory effect was significantly reduced in adult rats. No further changes were noticeable in old animals. D(2) receptors negatively coupled to cAMP generation were demonstrated by incubating hippocampus membrane particles with SCH 23390 plus DA or with D(2) receptor agonists quinpirole or bromocriptine. The D(2) inhibitory effect on cAMP generation was unchanged in the three age groups. No difference was detectable between young, adult and old rats in the activation of cAMP production by forskolin.

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Effect of long term hydergine treatment on the age-dependent loss of mossy fibers and of granule cells in the rat hippocampus.

The effects of senescence and of long-term Hydergine treatment on the density and pattern of mossy fibers and on the number of granule cells of the dentate gyrus were studied in the rat hippocampus. Timm's technique for the histochemical demonstration of tissue stores of zinc, associated with quantitative image analysis and microdensitometry, was used for the study of mossy fibers. Consistent with our previous studies, we observed an age-related reduction both in the area occupied by mossy fibers and in the intensity of Timm staining in the mossy fiber area. Moreover, the density of granule cells in the dentate gyrus of hippocampus was reduced with age. Hydergine administration (1 and 3 mg/kg/day, p.o.), started when the rats were 17 months old and continued for 4 months, significantly increased the area occupied by mossy fibers and the intensity of Timm staining in the hippocampus of senescent animals. Moreover, Hydergine treatment was found to counteract the age-dependent decrease in granule cell number in the dentate gyrus of the hippocampus. These findings suggest that treatment with Hydergine is effective in counteracting or in slowing down the morphological disorganization observable in the hippocampal formation with advancing age. Moreover, it is possible that the effects of Hydergine administration in elderly patients might be related to an effect at the level of the hippocampus.

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Age-related changes of the noradrenergic innervation of the uterine vasculature: a fluorescence histochemical study.

Age-related changes in the density of the noradrenergic perivascular plexus supplying the uterine artery and its intrauterine branches were studied in rats 4, 12 and 24 months old using the glyoxylic acid fluorescence technique. Moreover, uterine noradrenaline levels were determined by means of high pressure liquid chromatography with electrochemical detection. No changes in the density of noradrenergic innervation or in uterine noradrenaline levels were noticeable in 12 month in comparison with 4 month rats. In contrast, a significant decrease in the density of the noradrenergic perivascular plexus of uterine artery and of its intrauterine branches as well as decrease in noradrenaline concentrations of uterine horns and cervix were observed in 24 month rats. The above findings indicate an age-related impairment of uterine noradrenergic innervation.

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Nucleus basalis magnocellularis lesions impair mossy fiber system in rat hippocampus: a quantitative histochemical and ultrastructural study.

Lesions of the nucleus basalis magnocellularis (NBM) cause depletion of choline acetyltransferase (ChAT) in the cerebral cortex and behavioral changes consisting of impaired ability to learn avoidance tasks. Since hippocampal mossy fibers (MF) are involved in the elaboration of passive avoidance responses, we analyzed MF by means of Timm's histochemical technique and electron microscopy, to find out whether monolateral lesions of NBM had any effect on MF system. NBM-lesioned rats, 3 weeks after lesioning, showed a significant and progressive decrease in the density of Timm staining as well as significant changes of the morphology of synapic boutons of the MF. These results suggest that, although NBM does not send direct projections to the hippocampus, lesions of this nucleus may have a neurodegenerative effect on the intrahippocampal pathway involved in avoidance responses.

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The noradrenergic innervation of the kidney in old Wistar rats.

Age-related changes of the sympathetic (noradrenergic) innervation of the kidney were studied in young (3 months) and old (25 months) female Wistar rats by means' of high-pressure liquid chromatography (HPLC) with electrochemical detection and catecholamine histofluorescence techniques. Body and kidney weights were significantly increased in old rats. Renal noradrenaline levels were slightly but not significantly decreased in aged animals. The density of fluorescent catecholaminergic nerve fibres was significantly decreased in old rats, primarily within branches of renal artery (at the hilum) and within interlobular and cortical radial arteries. However, in old rats the number of axonal varicosities corresponding to the site of neurotransmitter release was slightly increased in interlobular and cortical radial arteries but not in hilar branches of the renal artery. The number of cortical tubules supplied with a catecholaminergic innervation remarkably decreased with age. These findings are indicative of age-dependent changes of the intrarenal noradrenergic innervation in Wistar rats. The lack of correspondence between the results obtained using HPLC and catecholamine histofluorescence techniques underscore the importance of evaluating the age-related changes of autonomic innervation using more than one methodology.

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Age-related changes in substance P and vasoactive intestinal polypeptide immunoreactivity in the rat stomach and small intestine.

Immunoreactivity for substance P (SP-LI) and vasoactive intestinal polypeptide (VIP-LI) in the stomach, duodenum, jejunum and ileum of young (3-month-old), adult (12-month-old) and old (28-month-old) male Wistar rats were determined by radioimmunoassay. SP-LI and VIP-LI did not show changes in the stomach or in the small intestine portions investigated in adult in comparison with young rats. In old rats SP-LI levels were unchanged in the stomach and in the duodenum, reduced in the jejunum and increased in the ileum. VIP-LI concentrations were unchanged in the stomach, and remarkably reduced in the duodenum, jejunum and ileum of old rats. Since the two neuropeptides investigated are localized primarily within different intrinsic gastrointestinal neurons, the present findings suggest that the various populations of gastrointestinal neurons are affected in a different manner during aging.

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Age-related anatomical changes in the rat hippocampus: retardation by choline alfoscerate treatment.

The age-related anatomical changes in the rat hippocampus were evaluated in male Sprague-Dawley rats of 3 (young), 12 (mature) and 24 (aged) months by counting the number of nerve cells in the CA1 and CA3 fields and in the dentate gyrus and by measuring the density of Nissl bodies in the cytoplasm of the pyramidal and granule neurons of the above areas. Moreover, the effect of 3 months choline alfoscerate treatment on the anatomical parameters examined was evaluated. The number of pyramidal neurons of the CA1 field and of granule neurons of the dentate gyrus was not significantly changed between young and mature animals, but it was decreased in aged rats. The number of pyramidal neurons of the CA3 field showed a progressive age-dependent reduction. The density of Nissl bodies was the highest in the cytoplasm of pyramidal or granule neurons in mature rats followed in descending order by young and aged animals. Choline alfoscerate treatment counteracted the age-related loss of nerve cells in the 3 hippocampal portions examined and slow-drown the decrease of Nissl bodies in the cytoplasm of pyramidal or of granule neurons in the hippocampus. The significance of changes induced by choline alfoscerate in the hippocampus of aged rats and the possible mechanism of action of the compound are discussed.

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Changes in the intensity of sulfide staining in fronto-parietal cortex of the rat following nucleus basalis magnocellularis lesions: possible relevance to Alzheimer's disease.

The sulfide staining technique, known also as neo-Timm staining, predominantly stains associational fibres arising from cortical interneurons located primarily in the neuropil of layers I-III of the rat cerebral cortex. The density of these fibres, considered to have a possible role in cognitive and mnemonic processes, has been demonstrated to be related to the density of zinc-containing presynaptic buttons in the cerebral cortex. The unilateral injection of ibotenic acid into the nucleus basalis magnocellularis (NBM) resulted in no changes in the density of sulfide staining in the first 3 weeks after neurotoxin injection and in a significant loss of sulfide staining in the neuropil of cortical layers I-III 4 weeks after NBM lesion in the fronto-parietal cortex ipsilaterally to the lesion. These data suggest that unilateral lesioning of the NMB may cause changes of chemo-specific zinc-containing intracortical pathways. Moreover, they indicate that, in a manner similar to that described in the brain of Alzheimer's disease patients, NBM-lesioned rats show a decrease of zinc tissue stores in the fronto-parietal cortex.

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PubMedDate not supplied

Effect of choline alfoscerate treatment on changes in rat hippocampus mossy fibres induced by monolateral lesioning of the nucleus basalis magnocellularis.

We have recently demonstrated that monolateral lesions of the Nucleus Basalis Magnocellularis (NBM), which is a nucleus sending cholinergic projections to the fronto-parietal cortex, cause a loss in the intensity of Timm staining in the intrahippocampal pathway of mossy fibres (MF). Moreover, these lesions induce ultrastructural changes consistent with the occurrence of degeneration of presynaptic buttons of MF. The present study was designed to quantify the effects of NBM lesioning on the morphology of the presynaptic buttons of MF. Moreover the effects of 4-week choline alfoscerate (alphaGFC) treatment on the density of Timm staining and on the ultrastructure of presynaptic buttons of MF were assessed, alphaGFC, which was given at an oral daily dose of 100 mg/kg, is a precursor in the biosynthesis of several brain phospholipids which increases the availability of choline in the nervous tissue. Monolateral lesions of NBM cause, 4 weeks after lesioning, a significant decrease in the intensity of Timm staining in the MF area accompanied by a loss of about 23% of presynaptic buttons of MF. Moreover about 40% of presynaptic buttons of MF show an impaired morphology. alphaGFC administration restored the intensity of Timm staining in the MF area. In alphaGFC-treated rats, the loss of presynaptic buttons and the number of impaired buttons were reduced to about 12% and 27%, respectively in comparison with non-treated animals. These results confirm and extend our previous observations indicative of the occurrence of transneuronal degenerations in the MF of the hippocampus after monolateral NBM lesioning. Moreover these findings show that alphaGFC treatment is able to counter in part these degenerative changes.

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Age-related changes in sulfide-silver stainable fibres in the rat cerebral cortex.

The present study was designed to assess the age-dependent changes in sulfide-silver stainable fibres in frontal, parietal and occipital cortex areas of the rat cerebral cortex. Male Sprague-Dawley rats of 2 months (young), 12 months (adult) and 24 months (aged) were used. Sulfide-silver stainable fibres, which represent predominantly zinc-containing associational fibres arising from local cortical interneurons, were visualized using the neo-Timm histochemical technique. The density of sulfide-silver stainable fibres within the neuropil of laminae I-III (upper zone) and of lamina V (lower zone) of the different cerebral cortex areas was assessed microdensitometrically. In the frontal and parietal cortices the density of sulfide-silver stainable fibres was higher in adult and in aged than in young rats both in the upper and in the lower zones. No significant differences were noticeable in the density of sulfide-silver stainable fibres between adult and old rats. In the occipital cortex the density of sulfide-silver stainable fibres was similar in young or adult rats. but was remarkably increased in old animals. The possibility that the increase in the density of sulfide-silver stainable fibres represents a compensatory mechanism in the cerebral cortex area showing the most consistent nerve cell loss is discussed.

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Age-related changes in the visual cortex: a review.

The main age related changes in visual cortex are reviewed. The visual cortex (occipital cortex, areas 17-19) undergoes a variety of anatomical, biochemical and functional changes with aging. From a morphological point of view the visual cortex loses nerve cells mainly in the last period of life. From a biochemical point of view cholinergic, serotonergic, and GABAergic neurotransmissions seem to be the most remarkably affected. In terms of functional correlates, a decline of several activities of the visual cortex has been documented in the elderly. Due to the importance of visual cortex in the realization of visual function, the influence of aging on this cerebrocortical area requires a more detailed analysis.

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Influence of ipsilateral lesions of the nucleus basalis magnocellularis and of choline alphoscerate treatment on histochemically reactive zinc stores and on the ultrastructure of the rat frontal cortex.

The influence of ipsilateral lesions of the nucleus basalis magnocellularis (NBM) and of choline alphoscerate treatment on histochemically reactive zinc stores and on the ultrastructure of the neuropil of layer III of the frontal cortex were investigated in the rat. In control animals a dark-brown staining was developed in the neuropil of layers I-III of the frontal cortex. Lesions of the right NBM caused a marked reduction in the density of sulphide-silver staining in the right frontal cortex 4 weeks post lesion. Moreover, changes in the morphology and in the density of synaptic buttons in the neuropil of layer III of the cerebral cortex were also noticeable. Concomitant treatment for 4 weeks with choline alphoscerate restored the density of sulphide-silver staining in the right frontal cortex and countered in part changes of synaptic buttons of the neuropil of layer III of the frontal cortex. These findings suggest that the loss of cerebrocortical histochemically reactive zinc stores occurring in NBM-lesioned rats is due to the alterations of synaptic contacts in the frontal cortex and that treatment with choline alphoscerate may counter these degenerative changes.

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PubMedDate not supplied

The noradrenergic innervation of spinal cord blood vessels in old rats.

The density and pattern of the sympathetic noradrenergic innervation of the extramedullary and intramedullary blood vessels of the spinal cord was studied in 3-, 12- and 25-month-old male Wistar rats using combined catecholamine histofluorescence and quantitative image analysis techniques. The study of innervation of intramedullary vessels was accomplished in spinal cord-transected rats to avoid the interference of descending spinal monoamine fibres in the observations. No age-related changes in the density of noradrenergic innervation of the anterior spinal artery or of sympathetic fibres associated with spinal cord blood vessels occurred. These results suggest that unlike perivascular noradrenergic nerves supplying the cerebrovascular tree, the sympathetic innervation of spinal cord blood vessels does not undergo age-dependent changes. It cannot be excluded that the lesser vulnerability of the spinal compared to the cerebral vascular tree to certain kinds of age-related diseases, may depend on the unchanged sympathetic trophic regulation of spinal vessels with age.

Adrenergic Fibers↗

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Age-related changes in sulfide-silver staining in the rat neostriatum: a quantitative histochemical study.

The density and distribution of sulfide-silver staining in the neostriatum of 3-, 12-, and 24-month-old male Sprague-Dawley rats were analyzed using the neo-Timm sulfide-silver histochemical technique associated with microdensitometry. This technique stains zinc-containing terminals in the striatum and the density of neo-Timm staining is considered to be parallel to the density of synaptic boutons containing zinc. In the neostriatum sulfide-silver, staining was intense in the matrix, although the striosomes did not show appreciable reactivity. The density of sulfide-silver staining was significantly reduced (p less than 0.001) in the matrix of 12-month-old in comparison to 3-month-old rats. No further changes were noticeable between 24- and 12-month-old rats. In contrast, the area and the perimeter of neostriatum that were assessed by quantitative image analysis did not show age-related changes. The present results indicated that similar to the observations for a variety of neurochemical parameters of rat neostriatum such as local cerebral glucose utilization, cholinergic muscarinic receptors, and dopamine D-1 receptors, zinc-containing striatal terminal were primarily decreased between young and adult subjects but not between adult and aged animals.

Aging↗