title: Stimulation of renal afferent fibers leads to activation of catecholaminergic and non-catecholaminergic neurons in the medulla oblongata.
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.
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Erika E
authors.initials: EE
authors.lastname: Nishi
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Beatriz S
authors.initials: BS
authors.lastname: Martins
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Maycon I O
authors.initials: MI
authors.lastname: Milanez
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Nathalia R
authors.initials: NR
authors.lastname: Lopes
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Jose F
authors.initials: JF
authors.lastname: de Melo
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Roberto B
authors.initials: RB
authors.lastname: Pontes
authors.affiliation: Laboratory of Genetics and Molecular Cardiology, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Adriana C
authors.initials: AC
authors.lastname: Girardi
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Ruy R
authors.initials: RR
authors.lastname: Campos
authors.affiliation: Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil. Electronic address: bergamaschi.cassia@unifesp.br.
authors.forename: Cássia T
authors.initials: CT
authors.lastname: Bergamaschi
mesh_terms: D000344:Afferent Pathways / Q000166:cytology / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002395:Catecholamines / Q000378:metabolism*; D004558:Electric Stimulation; D006339:Heart Rate / Q000502:physiology; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000294:innervation* / Q000378:metabolism*; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017208:Rats, Wistar; D012018:Reflex / Q000502:physiology; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D002395:Catecholamines; D016760:Proto-Oncogene Proteins c-fos; C000613387:Slc9a3 protein, rat; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D014446:Tyrosine 3-Monooxygenase
keywords: NHE3; NTS; RVLM; Renal afferents; Renorenal reflex; Tyrosine hydroxylase