Involvement of astrocyte-neuron lactate shutte mechanism in the cardiovascular, drinking intake and neuroendocrine response induced by central angiotensin II (ANG-II)
Federal University of Paraiba (UFPB)
Department of Biotechnology
Josiane de Campos Cruz
Josiane de Campos Cruz
English, Spanish, Portuguese
4 weeks
Cities/Months Jan Feb Mar Apr May Jun Jul Augt Sep Oct Nov Dec
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Type of Research Project
- Basic science
What is the background of the project?
Recently we have shown that hypothalamic circumventricular glial cells are involved in drinking behavior and in the neuroendocrine responses induced by central ANG-II (Flõr et al, 2018, Frontiers in Physiology). It is known that lactate in the central nervous system (CNS) is an important neuron nutritional molecule, but nowadays a blunt of studies have shown that lactate in the SNC also has a neuronal modulatory function. The major source of lactate in the CNS provide from astroglial cells. Concerning that, several studies have suggested that lactate in the subfornical (SFO) nuclei are involved in the salt avoidment behavior induced by dehydration. Considering that lactate in the SFO, the central nucleus failure in blood-brain barrier and a central key of circulating ANG-II, are involved in the behavioral responses induced by a hydromineral imbalance. Our hypothesis is that pressor response, water, and sodium intake, as well as vasopressin and oxytocin plasma release induced by central ANG-II, are blunted by lactate.
What is the aim of the project?
To evaluate the involvement of astrocyte-neurons lactate shutte mechanism in the central ANG-II induced cardiovascular, neuroendocrine and drinking behavioral responses.
What techniques and methods are used?
Microinjection of ANG-II and lactate or lactate synthase inhibitor in the lateral ventricle (LV) of awake rats (stereotaxia); directly recording of cardiovascular parameters (arterial catheterization); metabolic cage (measurement of sodium and water intake) and respiratory frequency recording. 1st stage Stereotaxia: The student will learn how to perform stereotaxia surgery, to implant guide-cannulae into the lateral ventricle in the central nervous system (CNS). After animals recovering from surgery (5-6 days after), students will learn how to perform microinjection in the SNC of awake rats. To stereoaxia surgery, the rats are deeply anesthetized and placed in a stereotaxic apparatus. Then, it is made a longitudinal incision in the skin of the head and a little hole in the skull is performed for the perpendicular introduction of the 15-mm-long stainless steel guide-cannulae. The guide-cannula is usually fixed with watch screws and closed with a mandrel until the experimental time.The animals are allowed 4–5 days to recover from stereotaxic surgery. 2nd stage Artery catheterization and cardiovascular recordings in awake rats: The student will learn how to perform artery catheterization and cardiovascular recording in awake rats. First, the student will learn how to perform intraperitonial anesthesia and then how to perform the surgery to Insert a polyethylene catheter into the femoral artery and how to do the catheter subcutaneously exteriorization in the back of the neck, to prevent the rat from pulling the catheters. On a subsequent day after catheterization, the femoral catheter in the femoral artery will flush with heparin saline to prevent clotting and then will be connected to a computer-driven data to recording cardiovascular parameters by AD Instrument software. The students will learn how to work with the AD instrument software. 3rd group Metabolic cage: The student will learn how to collect and measure liquid and food intake, as well as, urine excretion in animals located in a metabolic cage. 4rd group Respiratory recordings in awake rats: Student will learn how to perform whole-body plethysmograph method in rats.
What is the role of the student?
- The student will observe the practical experiments but will be highly involved in the analysis of the results
- The tasks will be done under supervision
What are the tasks expected to be accomplished by the student?
The students will perform intraperitoneal rats anesthesia; position rats' head in the stereotaxic, insert a cannula into the femoral artery and collect urine, water and food intake from the metabolic cage. To learn all of this technics the students will be taught and accompanied by our Ph.D. students. After the experiments, the students will be taught how to collect and analyze the data. One day per week, students will participate in our seminars, where we discuss our results, as well as, present and discuss scientific reports. The students will be encouraged to actively participated in these weekly seminars.
Will there be any theoretical teaching provided (preliminary readings, lectures, courses, seminars etc)
Yes, the student will receive the needed theoretical support before to start the practical analysis. To learn all of this technics the students will be taught by our Ph.D. students and the scientific and theoretical part will be learned by a weekly seminar.
What is expected from the student at the end of the research exchange? What will be the general outcome of the student?
- The student will prepare a poster
What skills are required of the student? Is there any special knowledge or a certain level of studies needed?
It is required that the students have a basic notion about central nervous, respiratory and cardiovascular systems, as well as, motivated to learn how to proceed with animals experiments.
Are there any legal limitations in the student’s involvement
Type of students accepted
This project accepts:
- Students in biomedical fields
- Front Physiol. 2018 May 1;9:430. doi: 10.3389/fphys.2018.00430. eCollection 2018.