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Dietary salt intake enhances sympathetic responses to central sodium and sciatic afferent activation
Author(s) -
Stocker Sean D
Publication year - 2013
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.27.1_supplement.695.6
Subject(s) - splanchnic , stimulation , endocrinology , heart rate , medicine , chemistry , baroreceptor , splanchnic nerves , lumbar , blood pressure , rostral ventrolateral medulla , sympathetic nervous system , anesthesia , hemodynamics , anatomy
Previous studies indicate that increased dietary salt intake enhances sympathetic nerve activity (SNA) and arterial blood pressure (ABP) responses evoked from the rostral ventrolateral medulla. The present study sought to extend these observations and determine whether SNA and ABP responses to physiological stimuli are also enhanced. Male Sprague‐Dawley rats were fed 0.1% (low) or 4.0% (high) NaCl chow for 14–16 days. Then, animals were anesthetized with Inactin, and various sympathetic reflexes were tested. Electrical stimulation (1–20 Hz, 1 ms pulse, 500 uA) of sciatic afferents produced frequency‐dependent changes in SNA and ABP in both groups. However, rats ingesting 4% versus 0.1% NaCl displayed significantly larger increase in lumbar SNA (5Hz: 213±25 vs 146±15%), renal SNA (5Hz: 187±24 vs 120±11%), splanchnic SNA (5Hz: 203±21 vs 136±9%), heart rate (5Hz: 21±4 vs 13±2 bpm), and mean ABP (5Hz: 28±2 vs 12±2mmHg). Similarly, rats ingesting 4% versus 1% NaCl displayed greater increases in lumbar SNA (128±9 vs 112±2%) and mean ABP (12±1 vs 7±2mmHg) in response to intracerebroventricular infusion of 1M NaCl (5ul/10min). These findings suggest that increased dietary NaCl sensitizes central sympathetic networks to produce larger changes in SNA and ABP.