Journal of neuroscience methods
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J. Neurosci. Methods · Jan 2012
An implantable triple-function device for local drug delivery, cerebrospinal fluid removal and EEG recording in the cranial subdural/subarachnoid space of primates.
Transmeningeal pharmacotherapy for cerebral cortical disorders requires drug delivery through the subdural/subarachnoid space, ideally with a feedback controlled mechanism. We have developed a device suitable for this function. The first novel component of the apparatus is a silicone rubber strip equipped with (a) fluid-exchange ports for both drug delivery and local cerebrospinal fluid (CSF) removal, and (b) EEG recording electrode contacts. ⋯ The entire apparatus was implanted in 5 macaque monkeys, with the subdural strip positioned over the frontal cortex and the minipump assembly secured to the cranium under a protective cap. The system was successfully tested for up to 8 months for (1) transmeningeal drug delivery using acetylcholine (ACh) and muscimol as test compounds, (2) RF-transmission of neocortical EEG data to assess the efficacy of drug delivery, and (3) local CSF removal for subsequent diagnostic analyses. The device can be used for (a) monitoring neocortical electrophysiology and neurochemistry in freely behaving nonhuman primates for more than 6 months, (b) determining the neurobiological impact of subdural/subarachnoid drug delivery interfaces, (c) obtaining novel neuropharmacological data on the effects of central nervous system (CNS) drugs, and (d) performing translational studies to develop subdural pharmacotherapy devices.
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J. Neurosci. Methods · Jan 2012
Brain oxygen tension monitoring following penetrating ballistic-like brain injury in rats.
While brain oxygen tension (PbtO(2)) monitoring is an important parameter for evaluating injury severity and therapeutic efficiency in severe traumatic brain injury (TBI) patients, many factors affect the monitoring. The goal of this study was to identify the effects of FiO(2) (fraction of inspired oxygen) on PbtO(2) in uninjured anesthetized rats and measure the changes in PbtO(2) following penetrating ballistic-like brain injury (PBBI). Continuous PbtO(2) monitoring in uninjured anesthetized rats showed that PbtO(2) response was positively correlated with FiO(2) (0.21-0.35) but PbtO(2) remained stable when FiO(2) was maintained at ∼0.26. ⋯ In PBBI rats, PbtO(2) was significantly reduced by ∼40% (16.9 ± 1.2 mm Hg) in the peri-lesional region immediately following unilateral, frontal 10% PBBI compared to sham rats (28.6 ± 1.7 mm Hg; mean ± SEM, p<0.05) and the PBBI-induced reductions in PbtO(2) were sustained for at least 150 min post-PBBI. Collectively, these results demonstrate that FiO(2) affects PbtO(2) and that PBBI produces acute and sustained hypoxia in the peri-lesional region of the brain injury. This study provides important information for the management of PbtO(2) monitoring in this brain injury model and may offer insight for therapeutic strategies targeted to improve the hypoxia/ischemia state in the penetrating-type brain injury.
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J. Neurosci. Methods · Jan 2012
Plate reader-based assays for measuring cell viability, neuroprotection and calcium in primary neuronal cultures.
Drug discovery and development efforts critically rely on cell-based assays for high-throughput screening. These assay systems mostly utilize immortalized cell lines, such as human embryonic kidney cells, and can provide information on cytotoxicity and cell viability, permeability and uptake of compounds as well as receptor pharmacology. While this approach has proven extremely useful for single-target pharmacology, there is an urgent need for neuropharmacological studies to screen novel drug candidates in a cellular environment resembles neurons in vivo more closely, in order to gain insight into the involvement of multiple signaling pathways. ⋯ We here developed and optimized protocols for the use of primary cortical neuronal cells in high-throughput assays for neuropharmacology and neuroprotection, including calcium mobilization, cytotoxicity and viability as well as ion channel pharmacology. Our data show low inter-experimental variability and similar reproducibility as conventional cell line assays. We conclude that primary neuronal cultures provide a viable alternative to cell lines in high-throughput assay systems by providing a cellular environment more closely resembling physiological conditions in the central nervous system.