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Does commissural NTS (cNTS) drive RVLM neurons for hemodynamic (Hd) control in intact rats?
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.a511-d
Subject(s) - bicuculline , muscimol , saline , sonomicrometry , medicine , chemistry , rostral ventrolateral medulla , endocrinology , hemodynamics , anatomy , anesthesia , medulla oblongata , gabaa receptor , central nervous system , receptor
We investigated the role of cNTS in the Hd control during GABAergic blockade in the RVLM in intact rats. Male Wistar rats (300–350g, N=6–7/group), chloralose‐anesthetized (60mg/kg, i.v.), tracheostomized, artificially‐ventilated, and with miniaturized Doppler flow probes around the superior mesenteric, abdominal aorta and left renal artery were used. Bicuculline (BMI, 2 mM, 60 nL) injected bilaterally into the RVLM decreased the hindlimb (HC, −37±11%), mesenteric (MC, ‐60±11%) and renal (RC, −48±10%) conductances compared to baseline, and increased MAP (195±9 vs. 119±4 mmHg baseline). The control group also showed similar responses to BMI in the RVL. After 5 min, muscimol (MS, 6 mM, 60 nL) or saline (60 nL, control group) into the midline cNTS similarly increased MC (109±54 and 30±15%, respectively) and RC (40±10 and 71±33%, respectively), but MAP only reduced to 155±7 mmHg with MS. Subsequent MS or saline (20 nL, control group) bilaterally into the lateral cNTS produced no changes on HC, MC or RC, but MAP decreased to 120±3 mmHg with MS. The data suggest that cNTS does not mediate the decrease in HC, MS and RC due to BMI in the RVLM in intact rats. Supported by FAPESP, CNPq‐PRONEX, NEPAS.