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Role of arterial baroreceptors on commissural NTS (cNTS) neurons involved in hemodynamic (Hd) control
Author(s) -
Sato Monica Akemi,
Morrison Shaun F,
Lopes Oswaldo U,
Colombari Eduardo
Publication year - 2007
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.21.5.a512-c
Subject(s) - baroreceptor , hemodynamics , mean arterial pressure , medicine , sonomicrometry , saline , anesthesia , muscimol , cardiology , anatomy , chemistry , blood pressure , heart rate , gabaa receptor , receptor
We evaluated if the baroreceptors influence the cNTS in the Hd control during GABAergic blockade in the RVL. Male Wistar rats (300–350g), 10 days sino‐aortic denervated (N=6/group), cloralose‐anesthetized (60mg/kg, i.v.), tracheostomized, ventilated, and with Doppler flow probes around the superior mesenteric, abdominal aorta and left renal artery were used. Bicuculline (BMI, 2 mM, 60nL) bilaterally into the RVL decreased the hindlimb (HC, −51±11%), mesenteric (MC, −54±9%) and renal (RC, −69±9%) conductances compared to baseline, increasing mean arterial pressure (MAP) (198±9 vs. 107±4 mmHg baseline). After 5 min, muscimol (MS, 6 mM, 60nL) into the midline (m) cNTS produced no changes in the HC, MC and RC, but MAP reduced to 171±8mmHg. Subsequent MS (20nL) bilaterally into the lateral (lat) cNTS increased the HC (167±31%), and RC (210±66%) compared to MS into midline cNTS, reducing MAP to 94±2mmHg. In the control group, BMI into the RVL produced similar Hd changes. Saline into the mcNTS produced small increases in HC (10±8%), MC (17±10%) and RC (18±9%) compared to post‐BMI, and no changes on MAP. Saline into the latcNTS did not change HC, MC, and RC, but MAP decreased to 147±10mmHg. The baroreceptors tonically inhibit the latcNTS neurons, which excitate the RVL neurons. Supported by FAPESP, CNPq‐PRONEX, NEPAS.