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11
XXIII Congress of I.P. Pavlov Physiology Society
Astroglial Vesicular Network: Evolution and Function in Health and Disease
Robert Zorec1,2*
1 Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia;
2 Celica Biomedical, Tehnoloski park 24, 1000 Ljubljana, Slovenia. * Presenting e-mail: robert.zorec@mf.uni-lj.si
Astrocytes, the most heterogeneous glial cell type in the brain, have been scientifically neglected for almost a century. By being merely "nervenkitt", as proposed by Virchow in 1858, they were considered to play only subservient roles to neurons. However, in the last two decades a renewed interest into these cells emerged. Astrocytes, get excited when neurotransmitters bind to their membrane receptors and signal back to neurons by releasing their own transmitters. As in neurons this involves vesicles, which store chemicals termed gliotransmitters or more generally gliosignaling molecules. While the vesicle-based chemical signal release is similar to that in neurons, however it is much slower vs. that in neurons. The slow kinetics of this signaling makes them integrators that provide energy (astrocytes contain glycogen) to neurons in a similar time domain. Vesicle dynamics greatly depends on intermediate filaments, which get overexpressed in pathological conditions. Therefore, altered vesicle dynamics may be associated with the diseases such as amyotrophic lateral sclerosis, multiple sclerosis, autistic disorders, Alzheimer's disease, trauma, edema, and states in which astrocytes contribute to neuroinflammation. In multiple sclerosis, for example, fingolimod, a recently introduced drug, apparently also affects vesicle traffic and gliosignaling molecule release from astrocytes, indicating that this process may well be used as a new physiologic target for the development of new therapies.
Connector Device for Long-Term Stimulation of Neuronal Cultures Growing on Microelectrode Arrays
Y.I. Pigareva, A.A. Gladkov, V.N. Kolpakov, I.V. Mukhina, V.B. Kazantsev, A.S. Pimashkin
Lobachevsky State University of Nizhny Novgorod, Center of Translation Technology, Department of Neuroengineering, Laboratory of intellectual biomechatronic technology
Neuronal cultures in vitro can be used to study memory, learning and information processing in the brain. Bioelec-trical activity of the cultured networks in vitro differs from the normal physiological activity of the brain possibly because of absence of an afferent signal. One of the ways to simulate sensory inputs can be chronic electrical stimulation. In this study we present the connector device for long term stimulation of the neuronal network cultured on microelectrode arrays.
Neuronal cultures in vitro can be used to study memory, learning and transfer of information signals in the brain. The monolayer of neuronal cells is organized in a synaptically connected two-dimensional neural network. The formation and modification of the synaptic connections in the network can be investigated with electrophysiological methods [4].
Spontaneous bioelectrical activity registered in neural networks in vitro differs from normal physiological activity in the living brain [2]. This phenomenon can be explained by absence of an afferent signal [1, 3]. Functional development of neural networks in the brain is significantly modulated by sensory inputs and associated with an increase of the number of cells, its density and synaptic connectivity change.
However, most of the studies of the cultures are made without external stimulation that simulates sensory inputs. Some attempts of long-term stimulation were made, which consisted of single stimulation trial in three-four days a week and lasted no more than 40 minutes.
Here we present a device that allows long-term continuous stimulation of the neuronal cultures. We suggest that the morphological and functional organization of the culture and its activity which developed under such conditions will reproduce in vivo features.
Materials and methods
The presented device (connector) for chronic stimulation is intended for keep cell cultures grown on microelectrode arrays (MEA). MEAs consists of microelectrodes on a glass substrate and has conductive pads on perimeter. The
OM&P
Opera Med Physiol 2017 Vol. 3 (S1) 13
