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

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.

Journal Article↗

PubMedDate not supplied

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.

Journal Article↗

PubMedDate not supplied

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.

Journal Article↗