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The role of the renal sympathetic nerves in hypertension
Author(s) -
Barrett Carolyn J,
Malpas Simon C,
McBryde Fiona D,
Guild SarahJane
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.969.26
Subject(s) - medicine , blood pressure , heart rate , pathophysiology of hypertension , cardiology , sympathetic nervous system , lumbar , concomitant , sympathetic activity , reflex , anesthesia , mean arterial pressure , surgery
The development of hypertension is hypothesized to involve an inappropriate increase in renal sympathetic nerve activity (RSNA), and a concomitant blunting of the reflex response to blood volume changes. We tested this hypothesis using a rabbit model of hypertension, where hypertension was induced using a high salt diet coupled with an infusion of angiotensin II (20ng/kg/min). RSNA, arterial pressure and heart rate were measured via telemetry in rabbits living in their home cages continuously for a period of one week prior and 3 weeks after inducing the hypertension. The model of hypertension resulted in a slow increase in arterial pressure, with a mean increase in pressure of approximately 15mmHg. Over the first few days of angiotensin II infusion RSNA was suppressed, but as pressure was maintained RSNA increased to above baseline levels, thus nerve activity was inappropriately high for the given level of arterial pressure. In a second group of animals, using the same model of hypertension, we examined both the lumbar and renal sympathetic responses to a number of acute stimuli. While the lumbar and renal nerves responded similarly to rapid changes in arterial pressure, the responses to volume infusion were very different. Our results suggest that it is specifically RSNA control of blood volume control that is impaired in hypertension. Supported by the Health Research Council and Auckland Medical Research Foundation.