Analysis of nitrergic system in astrocytes after stimulation of ATPs receptors: Involvement evaluation of A1 and A2a adenosine receptors

• Grant number: 15/25107-8
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: February 10, 2016
• End date: June 09, 2016
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Debora Rejane Fior Chadi
• Grantee: Karina Lucatto Marra
• Supervisor: Ana Maria Ferreira de Sousa Sebastião
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Universidade de Lisboa, Portugal
• Associated to the scholarship: 15/08212-2 - Analysis of neuronal nitric oxide synthase (nNOS) levels after knockdown of adenosine receptors A1 and A2A in rats, BP.IC

Abstract

Adenosine plays a fundamental role on neural stimulation and sinaptic transmission in central nervous system (CNS), it is part of a group of substances that act as endogenous modulators. These substances regulate physiological activities in many organs, tissues and cells. A1 and A2 receptors are highly distributed in CNS and they have great affinity for adenosine, which is able to modulate cardiovascular control in the nucleus of the solitary tract (NST) of rats. This nucleus receives primary afferents of baroreceptors and chemoreceptors, enabling instantaneous homeostatic adjustments. Besides, a great amount of adenosine reuptake sites has been observed in the NST, suggesting a significant modulatory role of this substance in cardiovascular control. Nitric Oxide (NO) gas is a free radical synthesized by nitric oxide synthase (NOS), and found in NST neurons. NO induces a hypotensive effect in NST which might be triggered by A2aR activation. Astrocytes also make part of tripartite synapse, which combines presynaptic terminal, postsynaptic terminal and the associated astrocyte. In this kind of arrangement, astrocytes respond to stimulations through Ca2+ intracellular release, causing severe consequences. Neurotransmitters that increase calcium concentration in astrocytes generate nitric oxide, causing a retrograde modulation of neurotransmission. Despite synaptic activity and modulation by neurotransmitters, the control of nitric oxide synthesis in astrocytes it is not fully established in different systems. Thus, the purpose of this project is to develop astrocytes culture from brain rats and stimulate cells with ATP and adenosine receptor agonists. Modifications of intracellular Ca2+ and the amount of nitrite released in the medium are also going to be observed following A1 and A2a receptors activation. The goal of this project will be reached in the Laboratory of Prof. Ana Maria Sebastião - Universidade de Lisboa, where the student will learn concepts about neurotransmitter interactions, astrocytes cultures and the quantification of Ca2+ intracellular levels. The analyses will be completed in Brazil in subsequent steps. (AU)