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The vascular and sympathetic innervation of the carotid body: is it altered in hypertension?

Grant number: 18/16953-0
Support type:Scholarships abroad - Research Internship - Doctorate (Direct)
Effective date (Start): December 01, 2018
Effective date (End): May 31, 2019
Field of knowledge:Biological Sciences - Physiology
Principal Investigator:Helio Cesar Salgado
Grantee:Fernanda Brognara Penteado Dias
Supervisor abroad: Julian F. R. Paton
Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Local de pesquisa : University of Auckland, New Zealand  
Associated to the scholarship:17/05163-6 - Role of the parasympathetic and sympathetic autonomic nervous system in the modulation of sepsis in unanesthetized rats, BP.DD

Abstract

The interaction between the neural and the immune system is vital for the modulation of the innate immune response. Recent advances have considered the role of inflammation in the development of hypertension. Hypertensive patients exhibit increased sympathetic outflow that might contribute to the genesis and maintenance of the high blood pressure levels. Data suggest that the carotid body chemoreceptors may be involved in the sympathetic hyperactivity. The carotid bodies have been seen as a promising therapeutic target for treating hypertension. Studies conducted in Professor Julian F. R. Paton's laboratory indicates that in both humans and spontaneously hypertensive rats (SHR) the peripheral chemoreceptor reflex is constantly activated, resulting in excessive sympathetic outflow and hypertension. Purinergic receptors (P2X3) were found upregulated in petrosal chemosensitive neurones in SHR. This may result from reduced vasculature, hypertrophied arterioles and elevated sympathetic innervation of the arterioles in the carotid body of SHR. Thus, the present study will compare the density of vasculature and the sympathetic innervation of the carotid bodies of SHR versus Wistar rats. Carotid artery bifurcations, containing the carotid body, from SHR and Wistar rats will be perfused, fixed and sectioned on a cryostat and prepared for immunostaining. Endothelial cells will be stained with a fluorescent lectin and the vessel types will be identified based on their diameters and presence/amount of vascular smooth muscle using immunofluorescence. In addition, we will assess the densities of sympathetic fibres innervating arterial vessels using antibodies for tyrosine hydroxylase to identify sympathetic fibres and glomus cells within carotid bodies from hypertensive (SHR) and normotensive rats.