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Cardiovascular responses during static exercise after blockade of angiotensin receptor‐AT2 subtype within the rostral and caudal ventrolateral medulla
Author(s) -
Tedesco Anthony,
Ally Ahmmed
Publication year - 2009
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.23.1_supplement.958.5
Subject(s) - rostral ventrolateral medulla , medicine , angiotensin ii receptor type 1 , angiotensin ii , microdialysis , endocrinology , reflex , medulla , mean arterial pressure , blood pressure , heart rate , central nervous system
Angiotensin receptors (AR), classified into AR‐AT1 and AR‐AT2 subtypes, are located in different regions of the central nervous system, particularly within the cardiovascular control centers in the brainstem. We previously reported the role of AR‐AT1 receptors within the medulla on cardiovascular responses during the exercise pressor reflex (Neuroscience Research, 60(3): 340‐348, 2008). In this study, we investigated the role of angiotensin receptor‐AT2 subtype (AR‐AT2) within the rostral (RVLM) and caudal (CVLM) ventrolateral medulla in modulating increased cardiovascular responses during static muscle contraction using anesthetized rats. Bilateral microdialysis of a selective AR‐AT2 antagonist, PD123319 (10 µM), for 30 minutes into the RVLM augmented increases in mean arterial pressure (MAP) and heart rate (HR) during a static muscle contraction. After 60 minutes of discontinuation of the drug, MAP and HR values in response to a muscle contraction returned to baseline levels. In contrast, bilateral microdialysis of PD123319 (10 µM), into the CVLM attenuated cardiovascular responses during a static muscle contraction and the responses recovered after 60 minutes of discontinuation of the drug. These results demonstrate that medullary AR‐AT2 plays an important role in modulating cardiovascular function during the exercise pressor reflex.