Radiotracer Labeling of Brain Slices
Avital Schurr, Benjamin M. Rigor in BRAIN SLICES in BASIC and CLINICAL RESEARCH, 2020
A primary motivation for using brain slices is the ease of selectively altering the extracellular environment of the tissue. A large number of studies have utilized this advantage to model ischemia by reducing buffer pO2 and/or glucose. Two particularly systematic studies illustrate the value of this approach. In the first, hippocampal slices were exposed to various levels of low glucose and low pO2 and then synaptic activity was checked by orthodromic stimulation 30 min after return to standard conditions. It was possible to establish a 50% inhibitory dose for pO2 and glucose as a means of screening antihypoxic/anti-ischemic drugs.14 An advantage of this approach is that it is possible to create specific degrees of energy impairment, as shown by recent results from our laboratory (Figure 4). Thus, functional impairment of particular energy-dependent processes, such as tissue Ca++ accumulation, can be studied under defined energy states. A second valuable approach to brain slice ischemia employs transient anoxia/aglycemia as a model of transient global ischemia.15 This permits detailed study of the time course of energy metabolites during and after transient energy impairment.
Convulsant-Induced Neocortical Epilepsy
Carl L. Faingold, Gerhard H. Fromm in Drugs for Control of Epilepsy:, 2019
For more than 20 years there has been considerable effort directed at characterizing, and postulating the origin of the burst discharges (paroxysmal depolarization shifts, PDS) that can be recorded from neurons exposed to convulsant agents.40 Recently there has been much work with in vitro investigations using brain slice preparations or isolated cells in culture. Such experiments have provided important information about the physiology of individual cells and the synaptic, membrane, and ionic bases of neuronal bursting (for review see Chapter 5 and Ref. 41,42). Accompanying the data from these basic models, however, is an uncertainty about the operational significance of the observed phenomena for epilepsy within intact brain. Further, little attention has been paid to the heterogeneous nature of cells constituting the neocortex, with results from one cell group being generalized to all cell groups. The normal local circuit or more distant neuronal interactions that are essential for clinical epilepsy cannot be assured in the reduced cell population of a slice, where nearly every neuron is partially deafferented, axotomized, and dendrectomized, or in a cell culture where normal cortical networks are totally absent. Consequently, the clinical relevance of results obtained from these models, though interesting, cannot be assured.
Determination of Toxicity
David Woolley, Adam Woolley in Practical Toxicology, 2017
The nervous system, from the central nervous system or peripheral nervous system, presents more of a problem, given that its principal function is to transmit electrical impulses or transfer small amounts of quickly decaying chemicals at synapses between neurons or other receptors such as those on muscles. Some of the endpoints are the same as those for other single-cell systems, such as cytotoxicity, apoptosis, and proliferation. More specific endpoints include electrophysiological aspects such as ion channels, and enzyme studies can include acetyl cholinesterase and other markers of effect. Techniques such as patch-clamp electrophysiology and calcium imaging allow the user to understand, respectively, how single cells and groups of cells behave in response to certain stimuli. Advances in microscopy have allowed insight into how nervous tissues respond to electric fields. These cells may not necessarily represent the complex network of nervous tissue but give understanding into how single or groups of cells respond. Such methods tend to rely on primary cell cultures taken from animals, and although they may be three Rs compliant, animal use could still be high. On a larger scale, the brain is suitable for study in tissue slice preparations, and it is possible to isolate the various cell types for individual study. The drawback of these techniques, however, is that change in one aspect of this complex system does not necessarily directly correlate with effects in life. Brain slices can be studied with techniques such as electrophysiology, autoradiography, genetic analysis, and histopathological staining. They allow intact nervous systems to be investigated and experimented upon.
Regulation of LTP at rat hippocampal Schaffer-CA1 in vitro by musical rhythmic magnetic fields generated by red-pink (soothing) music tracks
Published in International Journal of Radiation Biology, 2023
Zijia Jin, Lei Dong, Lei Tian, Mei Zhou, Yu Zheng
SD rats were anesthetized with chloral hydrate at a concentration of 0.1 ml/20 g (10%), and their brains were quickly removed after decapitation and stored at 4 °C in a cutting solution with the following composition (in mM): sucrose 90, NaCl 87.2, KCl 2.5, MgCl2 7, CaCl2 0.5, NaH2PO4 1.25, NaHCO3 25, and glucose 16.7. Brain slices were sectioned using a vibrating tissue slicer VF-200 (Precision, Natick, MA) with a thickness of 400 μm per slice. During the process of cutting, the cutting solution was continuously perfused with a mixture of 95% O2/5%CO2 for 5–10 min. Brain slices were subsequently incubated in artificial cerebrospinal fluid (ACSF) for 1 h at a temperature of 33 °C. Composition (in mM): NaCl 120, KCl 2.5, MgSO4•7H2O 2, CaCl2 2, NaH2PO4•2H2O 1.25, NaHCO3 26 and glucose 10. All reagents were of analytical grade (Tianjin Fengchuan Chemical Reagent Technology Company). All brain sections were randomly assigned to either control or experimental groups.
Aging protects rat cortical slices against to oxygen-glucose deprivation induced damage
Published in International Journal of Neuroscience, 2020
Zulfiye Gul, Celaleddin Demircan, Deniz Bagdas, Rifat Levent Buyukuysal
Brain slices offer certain advantages over in vivo approaches that experimental conditions can be controlled and maintained as desired [33]. In contrary to cell cultures or tissue homogenates, brain slices can maintain structural integrity [34] or cell composition, such as functional neurons, locally released effectors and intercellular connections are also preserved [35]. Although brain slices metabolically differ from the in vivo tissues, they exhibit a similar pattern of metabolic responses to ischemic and reflow conditions and has been repeatedly shown as a useful technique in neuroscience for understanding the mechanisms and identifying possible therapeutic strategies against neurological disorders [34]. In addition to these advantages, brain slices model also allows to eliminating the effects of other aged organs and disadvantages of the methodological complications such as invasive surgical procedure, prolonged anesthesia and endotracheal intubation in our experiment. Thus, we preferred acute brain slices and used OGD-REO as in vitro ischemia model in present study.
Efficient brain uptake of piperine and its pharmacokinetics characterization after oral administration
Published in Xenobiotica, 2018
Tianjing Ren, Qianwen Wang, Chenrui Li, Mengbi Yang, Zhong Zuo
Based on the unbound fraction obtained from plasma and CSF, the unbound concentrations of piperine in plasma and CSF were calculated by taking total concentration times its unbound fraction. Since the brain slice method using intact brain that maintains its physiological mechanism, it could provide more accurate estimation of unbound brain concentration. So, the total brain concentration was divided by Vu,brain to obtain unbound brain concentrations. Unbound concentrations in brain, plasma and CSF versus time profiles are demonstrated in Figure 2(B). It was found that the unbound concentration levels in rat brain, plasma and CSF were comparable with coherence concentration change. The estimated unbound AUC0→∞ in brain, plasma and CSF were 533.20 hċng/g, 482.76 . and 359.61 hċng/ml, respectively. The ratio of unbound AUC0→∞ in brain to that in plasma (Kp,uu,brain) for piperine is 1.10 and ratio of unbound AUC0→∞ in CSF to that in plasma (Kp,uu,csf) is 0.74.
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