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Hemodynamic responses to electrical stimulation of the aortic depressor nerve in conscious l‐name hypertensive rats
Author(s) -
Salgado Helio Cesar,
Durand Marina Toledo,
Salgado Maria Cristina,
Castania Jaci Airton
Publication year - 2008
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.22.1_supplement.953.7
Subject(s) - atenolol , atropine , stimulation , medicine , bradycardia , baroreflex , hemodynamics , heart rate , anesthesia , blood pressure , reflex , mean arterial pressure
The hemodynamic responses to electrical stimulation of the aortic depressor nerve (ADN) were evaluated in conscious normotensive and L‐NAME hypertensive Wistar rats. In addition, it was also examined the relative role played by parasympathetic activation and sympathetic withdrawal during ADN stimulation. Hypertensive rats were obtained by means of L‐NAME dissolved in drinking water, given during 14 days. The animals were anesthetized (thiopental) for catheterization of femoral artery and vein, and placement of bipolar electrodes for ADN stimulation. Electrical stimulation of the ADN was applied during 20s (1mA, 2ms, and 5, 15, 30, 60 and 90 Hz), before and after atropine or atenolol. Hypertensive rats exhibited higher mean arterial pressure (MAP) (154±4 vs104±3 mmHg) and heart rate (HR) (394±8 vs 354±7 bpm) as compared to normotensive rats. Atenolol or atropine did not affect the hypotensive response in both groups. Atenolol attenuated (44%) the bradycardic response in L‐NAME hypertensive rats, but did not affect in normotensive rats. Atropine attenuated the bradycardic response in L‐NAME hypertensive (78%) and normotensive rats (71%). The results demonstrate a preserved baroreflex‐mediated decrease in MAP and HR in conscious L‐NAME hypertensive rats, and indicate that the withdrawal of the sympathetic drive plays a greater role in the reflex bradycardia in this hypertensive model. Support: FAPESP, CNPq.