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Evaluation of vasopressin action at the paraventricular nucleus of the hypothalamus level on cardiovascular parameters of salt-loaded rats

Grant number: 13/01605-3
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): May 01, 2013
Effective date (End): April 30, 2014
Field of knowledge:Biological Sciences - Physiology - Physiology of Organs and Systems
Principal Investigator:Vagner Roberto Antunes
Grantee:Karoline Martins dos Santos
Home Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Cardiovascular diseases have been the major health problem and the leading cause of death in the world, especially hypertension. Among several risk factor involved in the genesis of hypertension, high salt intake diet is one of them. Bad eating behavior, especially associated to high salt diet can lead to increase in plasma osmolarity, also called hyperosmolarity, which is able to affect the sympathetic autonomic outflow and the PVN is one of the key brain regions strictly involved in control of the sympathetic activity during osmotic stimuli. The PVN is composed by two distinct subgroups of neurons (parvo and magnocellular). Parvocellular neurons project to pre-motor sympathetic neurons located in the rostral ventrolateral medulla and/or pre-ganglionic sympathetic neurons in the intermediolateral cell column of the spinal cord, two important brain areas involved in the control of sympathetic outflow, and regulation of blood pressure levels. The magnocellular neurons of PVN projects to the posterior pituitary and they are responsible for the synthesis and release of vasopressin (VP). The VP is a nonapeptide with hormonal and neurotransmitter activity. In the central nervous system the VP is either synaptic released from axon collaterals or nonsynaptic released from the somatodendritic regions of magnocellular neurons and has its effects by acting via V1 receptors. It is well established in the literature that osmotic stimuli, such as salt-loading was able to evoke different responses at the distinct subgroups of the PVN neurons level and that VP may play an important role as a neuromodulator in this responses. Although, it has been already showing dendritic release of the VP within PVN nothing is known about the functional role of this neurotransmitter/neuromodulator on salt-induced hypertension. Therefore, the goal of this study is to investigate the role of endogenous vasopressin, through its action within PVN neurons, on blood pressure control of conscious salt-loaded animals.