Local action of the diabetogenic drug, streptozotocin, on glucose and energy metabolism in rat brain cortex.

Glucose is the principal source for energy production in the brain, and undisturbed glucose metabolism is pivotally significant for normal function of this organ. Peripheral glucose metabolism is impaired by streptozotocin (STZ), which induces diabetes mellitus. In this investigation, we have studied the local effects of intracerebroventricular (i.

Neuropeptide Y (NPY)-immunoreactive neurons in the primate fascia dentata; occasional coexistence with calcium-binding proteins: a light and electron microscopic study.

Neuropeptide Y (NPY)-containing neurons are known to be highly vulnerable following sustained electrical stimulation in rats and in humans suffering from temporal lobe epilepsy. This has been related to a strong excitatory input. In contrast, there is evidence that neurons containing calcium-binding proteins exhibit a high resistance under experimental seizure and hypoxia conditions.

Maintenance of peripheral dendrites of GABAergic neurons requires specific input.

This study demonstrates that the removal of a major hippocampal afferent system, the fibers from the entorhinal cortex, results in transneuronal changes in postsynaptic GABAergic inhibitory neurons. Following swelling of their distal segments, the peripheral dendrites of these cells retract from the termination zones of degenerating entorhinal fibers in the outer molecular layer of the fascia dentata and in stratum lacunosum-moleculare of the hippocampus proper. These dendritic alterations are long-lasting and do not seem to be restored by sprouting of other intact afferents.

Area-specific morphological and neurochemical maturation of non-pyramidal neurons in the rat hippocampus as revealed by parvalbumin immunocytochemistry.

The time course of the morphological differentiation of non-pyramidal neurons in the rat hippocampus shows an area specificity. Thus, non-pyramidal neurons in CA3 appear more mature than in CA1 at early postnatal stages. Physiological data provide evidence for an earlier maturation of GABA-mediated inhibition in CA3 in comparison to CA1.

Predominant abnormality in cerebral glucose utilization in late-onset dementia of the Alzheimer type: a cross-sectional comparison against advanced late-onset and incipient early-onset cases.

Global cerebral blood flow and the cerebral metabolic rates of oxygen, CO2, glucose and lactate were studied in 11 patients aged 61-78 years who had been clinically diagnosed as suffering from incipient late-onset dementia of the Alzheimer type (DAT), and in 7 patients aged 66-83 years, in whom advanced late-onset DAT had been diagnosed, using the Kety-Schmidt technique. In incipient late-onset DAT, the predominant abnormality was a 45% reduction in cerebral glucose utilization, whereas cerebral blood flow and the cerebral metabolic rate of oxygen were diminished by only 17% and 18%, respectively. A severe imbalance between oxygen utilization and glucose utilization thus became obvious.

Alterations of phospholipid metabolites in postmortem brain from patients with Alzheimer's disease.

To test the hypothesis that brain cell membranes degenerate in Alzheimer's disease (AD), we measured the levels of phospholipids, their water-soluble metabolites, and glycerophosphocholine (GPC) cholinephosphodiesterase activity in postmortem brain tissue from patients with AD and age-matched controls. We found significantly higher levels of the phospholipid catabolite GPC in AD brain. In contrast, choline and ethanolamine levels were significantly lower in AD, and phospholipid levels were slightly decreased.

Effects of changes in peripheral and cerebral glucose metabolism on locomotor activity, learning and memory in adult male rats.

Interactions of glucose and cognitive function have been reported both in the presence of elevated arterial blood glucose levels and with decreased cerebral glucose metabolism. In order to test the peripheral vs. central effects of this phenomenon, we induced irreversible hyperglycemia and depression of cerebral glucose metabolism in separate designs by means of either intraperitoneal (i.

Proportion of parvalbumin-positive basket cells in the GABAergic innervation of pyramidal and granule cells of the rat hippocampal formation.

Recent studies have indicated that hippocampal GABAergic neurons in both the dentate gyrus and Ammon's horn contain immunoreactivity for the calcium-binding protein parvalbumin (PARV). Although the distribution of PARV-positive neurons has been previously described, detailed quantitative electron microscopic studies of the PARV-positive axon terminals in the hippocampal formation are lacking. In the present study, immunocytochemical methods were used to localize PARV-positive neurons and axon terminals to determine their similarity to GABAergic neurons.

Late appearance of parvalbumin-immunoreactivity in the development of GABAergic neurons in the rat hippocampus.

The calcium-binding protein parvalbumin (PARV) is supposed to have a protective function under conditions of experimental seizure and hypoxia in a subgroup of GABAergic inhibitory neurons in the adult rat hippocampus. Here we studied the appearance of PARV immunoreactivity in rat hippocampal non-pyramidal cells during postnatal development in comparison to glutamate decarboxylase (GAD) immunoreactivity. PARV-immunoreactive neurons were not observed before postnatal day 7 whereas GAD-positive neurons and terminal-like puncta were present at postnatal day 2 (P2) and were frequent around P5.

Most somatostatin-immunoreactive neurons in the rat fascia dentata do not contain the calcium-binding protein parvalbumin.

A selective loss of somatostatin (SS)-containing neurons in the hilar region has been reported in patients suffering from temporal lobe epilepsy. Conversely, neurons containing calcium-binding proteins such as parvalbumin (PARV) are known to be very resistant under experimental seizure conditions. In this study, we analyzed the coexistence of SS and PARV in neurons of the rat fascia dentata by using serial semi-thin cryostat sections for pre-embedding immunocytochemistry.

Ammonia is endogenously generated in the brain in the presence of presumed and verified dementia of Alzheimer type.

The healthy, mature, non-starved brain was found to take up a small amount of ammonia on average 7.22 +/- 0.72 micrograms/100 g x min.

Axo-axonic chandelier cells in the rat fascia dentata: Golgi-electron microscopy and immunocytochemical studies.

Synaptic transmission can be blocked very efficiently by inhibitory synapses on axon initial segments. Inhibitory chandelier cells forming synapses on the axon initial segment of pyramidal neurons have been found in the neocortex and hippocampus proper. Here we describe an axo-axonic local circuit neuron in the rat fascia dentata that establishes synaptic contacts with axon initial segments of numerous dentate granule cells.

The parvalbumin-containing nonpyramidal neurons in the rat hippocampus.

The calcium-binding protein parvalbumin is considered to be involved in the control of intracellular ion homeostasis of highly active inhibitory neurons. A review of the light and electron microscopical features as well as the identified synaptic connections of these neurons is presented. Parvalbumin-containing neurons are mostly located within or in the vicinity of the granule or pyramidal cell layer.

Entorhinal fibers form synaptic contacts on parvalbumin-immunoreactive neurons in the rat fascia dentata.

The entorhinal cortex gives rise to a dense projection to the outer two-thirds of the dentate molecular layer. The main target neurons are the granule cells. This study demonstrates that entorhinal fibers labeled by anterograde degeneration also terminate on parvalbumin-containing non-granule cells in the rat fascia dentata.

Cerebral excess release of neurotransmitter amino acids subsequent to reduced cerebral glucose metabolism in early-onset dementia of Alzheimer type.

A massive cerebral release of amino acids and ammonia was found in early-onset dementia of Alzheimer type. Aspartate and glycine were liberated in high concentrations, whereas glutamate remained rather unchanged. This excess cerebral protein catabolism is due to a 44% reduction in cerebral glucose metabolism.

Cryostat sections for coexistence studies and preembedding electron microscopic immunocytochemistry of central and peripheral nervous system tissue.

Perfusion-fixed tissue blocks were incubated in high molar sucrose solutions, shock frozen in melting isopentane, and sectioned on a conventional cryostat. Semithin sections (2-4 microns) alternatingly stained for parvalbumin and glutamate decarboxylase enabled us to demonstrate the coexistence of both antigens in the same cell. Thick sections (40 microns) of central and peripheral nervous system tissue were immunostained and processed for correlated light and electron microscopic studies.

[The position of the supracondylar correction osteotomie during the treatment of the senile gonarthrosis (author's transl)].

The position of the supracondylar correction osteotomie during the treatment of the senile gonarthrosis is examined by controls of 17 patients with 21 performed osteotomies. The indication, the technique as well as the clinical and radiological results of the operation are critically dealt with. In case of a correct indication and when considering the contra-indication-like and existing strong osteoporosis, a distinct deficit of expansion and a most serious arthrosis-good results can be expected.