Stimulation of renal afferent fibers leads to activation of catecholaminergic and non-catecholaminergic neurons in the medulla oblongata

Author(s)

Nishi, Erika E. ; Martins, Beatriz S. ; Milanez, Maycon I. O. ; Lopes, Nathalia R. ; de Melo, Jr., Jose F. ; Pontes, Roberto B. ; Girardi, Adriana C. ; Campos, Ruy R. ; Bergamaschi, Cassia T.

• Document type: Review article
• Source: AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL; v. 204, p. 48-56, MAY 2017.
• Web of Science Citations: 2

Abstract

Presympathetic neurons in the rostral ventrolateral medulla (RVLM) including the adrenergic cell groups play a major role in the modulation of several reflexes required for the control of sympathetic vasomotor tone and blood pressure (BP). Moreover, sympathetic vasomotor drive to the kidneys influence natriuresis and diuresis by inhibiting the cAMP/PKA pathway and redistributing the Na+/H+ exchanger isoform 3 (NHE3) to the body of the microvilli in the proximal tubules. In this study we aimed to evaluate the effects of renal afferents stimulation on (1) the neurochemical phenotype of Fos expressing neurons in the medulla oblongata and (2) the level of abundance and phosphorylation of NHE3 in the renal cortex. We found that electrical stimulation of renal afferents increased heart rate and BP transiently and caused activation of tyrosine hydroxylase (TH)-containing neurons in the RVLM and non-TH neurons in the NTS. Additionally, activation of the inhibitory renorenal reflex over a 30-min period resulted in increased natriuresis and diuresis associated with increased phosphorylation of NHE3 at serine 552, a surrogate for reduced activity of this exchanger, in the contralateral kidney. This effect was not dependent of BP changes considering that no effects on natriuresis or diuresis were found in the ipsilateral-stimulated kidney. Therefore, our data show that renal afferents leads to activation of catecholaminergic and non-catecholaminergic neurons in the medulla oblongata. When renorenal reflex is induced, NHE3 exchanger activity appears to be decreased, resulting in decreased sodium and water reabsorption in the contralateral kidney. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 15/23858-6 - Effects of renal denervation on renal oxidative stress in experimental renovascular hypertension
• Grantee: Nathalia Rodrigues Lopes
• Support type: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 13/23741-6 - Evaluation of central mechanisms in the renorenal reflex and the role of afferent renal nerves in renovascular hypertension
• Grantee: Erika Emy Nishi
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 13/22522-9 - Role of renal sympathetic nerves on cardiovascular and renal alterations in renovascular hypertension
• Grantee: Ruy Ribeiro de Campos Junior
• Support type: Regular Research Grants
• FAPESP's process: 15/23809-5 - Brain areas involved in the cardiovascular system regulation activated by afferent renal fibers
• Grantee: Beatriz Silva Martins
• Support type: Scholarships in Brazil - Scientific Initiation