Search results for " format"
showing 10 items of 2156 documents
Modulation of hippocampal acetylcholine release after fimbria-fornix lesions and septal transplantation in rats
1997
Abstract Female Long–Evans rats sustained electrolytic lesions of the fimbria and the dorsal fornix causing a partial lesion of the septohippocampal pathway. Two weeks later, the rats received intra-hippocampal grafts of fetal septal cell suspensions. Nine to twelve months later, the release of acetylcholine (ACh) in the hippocampus of sham-operated, lesion-only and grafted rats was measured by microdialysis. The extent of cholinergic (re)innervation was determined by acetylcholinesterase (AChE) staining and densitometry. In both lesion-only and grafted rats, the ratio of ACh release to AChE staining intensity was increased as compared to sham-operated rats, indicating a loss of endogenous …
Nanocrystalline Hydroxyapatite Bone Substitute Leads to Sufficient Bone Tissue Formation Already after 3 Months: Histological and Histomorphometrical…
2012
Purpose: In this study the de novo bone formation capacity of a nanocrystalline hydroxyapatite bone substitute was assessed 3 and 6 months after its insertion into the human sinus cavity. Materials and Methods: Sinus cavity augmentation was performed in a total of 14 patients (n = 7 implantation after 3 months; n = 7 implantation after 6 months) with severely atrophic maxillary bone. The specimens obtained after 3 and 6 months were analyzed histologically and histomorphometrically with special focus on bone metabolism within the residual bone and the augmented region. Results: This study revealed that bone tissue formation started from the bone-biomaterial-interface and was directed into th…
Model-specific effects of bumetanide on epileptiform activity in the in-vitro intact hippocampus of the newborn mouse.
2007
The immature brain has a higher susceptibility to develop seizures, which often respond poorly to classical pharmacological treatment. It has been recently suggested that bumetanide, which blocks Na(+)-dependent K(+)-Cl(-)-cotransporter isoform 1 (NKCC1) and thus attenuates depolarizing GABAergic responses, could soothe epileptiform activity in immature nervous systems. To evaluate whether bumetanide consistently attenuates epileptiform activity, we investigated the effect of 10 microM bumetanide in five different in-vitro epilepsy models using field potential recordings in the CA3 region of intact mouse hippocampal preparations at postnatal day 4-7. Bumetanide reduced amplitude and frequen…
Urolithiasis Following Portacaval Shunt in Rats
1987
A reliable technique for a portacaval anastomosis (PCA) in rats was first published by Lee and Fisher 1961. Since then the biological and biochemical consequences have been studied extensively in numerous investigations. The occurrence of a urolithiasis following PCA was first reported by Herz et al. 1972. Disturbances of uric acid metabolism that were caused by the shunt were thought to be responsible. They should lead to an increased production of endogenous uric acid and thus to hyperuricosuria. Investigations that were published since then mainly focused on chemical stone analysis (Bichler et al. 1974; Rasenack et al. 1977; Wallace et al. 1984).
Water maze performance, exploratory activity, inhibitory avoidance and hippocampal plasticity in aged superior and inferior learners
2002
In 28- to 30-month-old rats, in vitro short-term and long-term potentiation (STP and LTP) were measured in area CA1 of the hippocampus in seven superior and seven inferior learners, that were selected from a pool of 40 rats based on water maze escape performance over a period of 9 days. The aim was to examine whether levels of STP and LTP could account for group differences in learning of water maze escape, spatial preference and wall (thigmotaxis)-avoidance and in short-term retention of an inhibitory avoidance task. There was no significant group difference in open-field exploration, i.e. the number of rearings. In contrast to expectation, the superior and inferior learners did not differ…
Characterization of choline efflux from the perfused heart at rest and after muscarine receptor activation.
1986
The resting efflux of choline from perfused chicken hearts varied from 0.4 to 2.6 nmol/g min, but was constant for at least 80 min in the individual experiments. The rate of choline efflux was found to be equal to the rate of choline formation in the heart, which, from the following reasons, was essentially due to hydrolysis of choline phospholipids. Cardiac content of choline phospholipids (7,200 nmol/g) was much higher than that of acetylcholine (5.5 nmol/g). Resting release of acetylcholine was 0.016 nmol/g min and, after inhibition of cholinesterase, only about 0.1 nmol/g min. Resting efflux of choline was reduced by mepacrine, a phospholipase A2 inhibitor, by perfusion with a Ca2+-free…
Selected peptides targeted to the NMDA receptor channel protect neurons from excitotoxic death
1998
Excitotoxic neuronal death, associated with neurodegeneration and stroke, is triggered primarily by massive Ca2+ influx arising from overactivation of glutamate receptor channels of the N-methyl-D-aspartate (NMDA) subtype. To search for channel blockers, synthetic combinatorial libraries were assayed for block of agonist-evoked currents by the human NR1-NR2A NMDA receptor subunits expressed in amphibian oocytes. A set of arginine-rich hexapeptides selectively blocked the NMDA receptor channel with IC50 approximately 100 nM, a potency similar to clinically tolerated blockers such as memantine, and only marginally blocked on non-NMDA glutamate receptors. These peptides prevent neuronal cell d…
Auditory cortical and hippocampal local-field potentials to frequency deviant tones in urethane-anesthetized rats: An unexpected role of the sound fr…
2015
Abstract The human brain can automatically detect auditory changes, as indexed by the mismatch negativity of event-related potentials. The mechanisms that underlie this response are poorly understood. We recorded primary auditory cortical and hippocampal (dentate gyrus, CA1) local-field potentials to serial tones in urethane-anesthetized rats. In an oddball condition, a rare (deviant) tone ( p = 0.11) randomly replaced a repeated (standard) tone. The deviant tone was either lower (2200, 2700, 3200, 3700 Hz) or higher (4300, 4800, 5300, 5800 Hz) in frequency than the standard tone (4000 Hz). In an equiprobability control condition, all nine tones were presented at random ( p = 0.11). Diffe…
Signaling through BMPR-IA regulates quiescence and long-term activity of neural stem cells in the adult hippocampus.
2010
SummaryNeural stem cells (NSCs) in the adult hippocampus divide infrequently, and the molecules that modulate their quiescence are largely unknown. Here, we show that bone morphogenetic protein (BMP) signaling is active in hippocampal NSCs, downstream of BMPR-IA. BMPs reversibly diminish proliferation of cultured NSCs while maintaining their undifferentiated state. In vivo, acute blockade of BMP signaling in the hippocampus by intracerebral infusion of Noggin first recruits quiescent NSCs into the cycle and increases neurogenesis; subsequently, it leads to decreased stem cell division and depletion of precursors and newborn neurons. Consistently, selective ablation of Bmpr1a in hippocampal …
Acute oral administration of low doses of methylphenidate targets calretinin neurons in the rat septal area.
2015
Methylphenidate (MPD) is a commonly administered drug to treat children suffering from attention deficit hyperactivity disorder (ADHD). Alterations in septal driven hippocampal theta rhythm may underlie attention deficits observed in these patients. Amongst others, the septo-hippocampal connections have long been acknowledged to be important in preserving hippocampal function. Thus, we wanted to ascertain if methylphenidate administration, which improves attention in patients, could affect septal areas connecting with hippocampus. We used low and orally administered methylphenidate doses (1.3; 2.7 and 5mg/Kg) to rats what mimics the dosage range in humans. In our model, we observed no effec…