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Exercise augments but sinoaortic denervation blocks noradrenergic signaling to PVN in trained normotensive rats (686.5)
Author(s) -
Michelini Lisete,
Santos Carla,
Ruggeri Adriana,
Braga Douglas,
Ceroni Alexandre
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.686.5
Subject(s) - endocrinology , medicine , baroreflex , basal (medicine) , hemodynamics , denervation , heart rate , chemistry , blood pressure , insulin
Exercise training (T) increases ascending NORergic signaling from NTS to PVN, improves baroreflex sensitivity (BrS) and reduces basal heart rate (HR). We evaluate the effects of sinoaortic denervation (SAD) and T on cardiovascular parameters and expression of PVN oxytocinergic (OTergic) and vasopressinergic (VPergic) neurons. SAD and SHAM rats were submitted to low‐intensity T or kept sedentary (S) for 3 month. After hemodynamic measurements, rats were euthanized; perfused brains were post‐fixed and cryoprotected. Sequential PVN slices (30 μm) were processed for OT, VP and dopamine β‐hydroxylase (DBH) immunoreactivity (ir); images were acquired and analyzed by Image J. In SHAM rats T reduced basal HR, increased BrS (328±8 b/min, 2.4±0.2 b/min/mmHg, ‐13% and +25% vs S controls), augmented the density of DBH terminals and OTir in ventromedial PVN and reduced VPir in the magnocelular PVN, without changing DBH signaling to this area. SAD markedly reduced basal OTir and VPir in both PVN areas and blocked functional and T‐induced effects on OTir and VPir. T‐induced afferent signaling, directed preferentially to preautonomic areas, increases the expression of OTergic neurons, contributing to the appearance of beneficial effects in intact T rats. SAD blocks these effects confirming that PVN signaling conveyed by baro‐ and chemoreceptors is essential to maintain neuronal tonicity and to mediate T‐induced effects Grant Funding Source : Supported by FAPESP, CNPq