Abstract
The purpose of this thesis is to study the effect of neurotransmitters on nerve cells and to develop advanced methods in the field of Neurobiology.Neurotransmitters are a group of chemicals released by nerve endings that allow transmission of cell-to-cell signals. They can also be named as a chemical messenger or chemical transmitter because of their ability to transmit nerve impulses from one cell to the next throughout the nervous system. They play an important role in shaping everyday life and functions. Their precise number is unknown, but more than 200 chemical messengers have been uniquely recognized.In recent years, a system of measuring the change in electrical potential of a single cell membrane or single-cell segment but at the cell population/tissue level has been developed. The Bioelectric Recognition Assay (BERA) is a method for detecting viruses and other bioactive substances based on the measurement of changes in the electrical properties of a cell group properly. It is ...
The purpose of this thesis is to study the effect of neurotransmitters on nerve cells and to develop advanced methods in the field of Neurobiology.Neurotransmitters are a group of chemicals released by nerve endings that allow transmission of cell-to-cell signals. They can also be named as a chemical messenger or chemical transmitter because of their ability to transmit nerve impulses from one cell to the next throughout the nervous system. They play an important role in shaping everyday life and functions. Their precise number is unknown, but more than 200 chemical messengers have been uniquely recognized.In recent years, a system of measuring the change in electrical potential of a single cell membrane or single-cell segment but at the cell population/tissue level has been developed. The Bioelectric Recognition Assay (BERA) is a method for detecting viruses and other bioactive substances based on the measurement of changes in the electrical properties of a cell group properly. It is possible to detect human and plant viruses in a specific, fast (less than 3 minutes), remarkably reproducible and economical way. The sensitivity of BERA is comparable to previous immunological, cytological and molecular techniques.This doctoral thesis is divided into two sections. The first section deals with the investigation of the effect of dopamine on nerve cells and more specifically the development of a functional test for the study of the in vitro interaction of dopamine neurotransmitters with dopamine receptor-bearing nerve cells for the purpose of evaluating different drug targets. The idea is based on the extremely rapid measurement of changes observed in the electrical properties of cultured mouse neuroblastoma (N2a) cells. Analysing the experimental data, a relatively close relationship was observed between dopamine concentration and cell membrane potential. At lower concentrations of dopamine (nanomolar) membrane depolarization was observed, while at higher concentrations (micromolar) cell membrane hyperpolarization was observed. The use of eticlopride, a dopamine D2-receptor antagonist, resulted in concentration-dependent membrane depolarization. In addition, a significant attenuation of cell membrane hyperpolarization was observed when cells were treated with sodium chloride. As determined by cyclic voltammetry, the bioelectric response to dopamine was highly correlated with the pattern of dopamine overflow by N2a cells. The novel approach was additionally used to evaluate the dopaminergic activity of chaste tree extracts (Vitex agnus-castus) as well as the activity of two well-known antipsychotics, haloperidol and olanzapine. This new concept offers many promising prospects for the development of an advanced system for the rapid functional characterization of neurotransmitters agonists and antagonists.The second section deals with the examination of the existence of non- chemical, distant cellular interactions between neuronal cells. The mechanism of cell-to- cell communication and the coordinated cellular responses they present are something that has been of great concern to the scientific community in recent years. The work in the present study focuses on non-chemical, distant cellular interactions (NCDCI) that are likely to be responsible for this communication. Recent experiments have suggested the field theory of conscious electromagnetic information (CEMI) as a possible explanation for this cell-to-cell communication. In the present work, using a bioelectric biosensor, we observed the emergence of distant communication between neuroblastoma cells providing evidence for this theory. This observation was made simultaneously with the observations of changes in the membrane potential of human SK-N-SH neuroblastoma cells that were physically separated from each other. The cells were divided into two groups naturally separated. In one group we had the "inducer" cells that were stimulated with dopamine, and in the other group, we had the "detector" cells which showed a synchronized response to the "inducer" cells, with the amplitude of the response decreasing as the distance increased. In order to investigate the nature of the mechanisms that cause the observed distant cell interactions, cell cultures were separated with barriers, which were non-transparent in certain frequency ranges of the electromagnetic radiation spectrum or treated with vinblastine, a vinca alkaloid, which binds tubulin, thereby inhibiting the assembly of microtubules. The mechanism responsible for cell-to-cell communication is discussed in accordance with the observed effects of coordinated changes in membrane potential.
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