Document Detail


Differing pattern of sympathoexcitation in normal-weight and obesity-related hypertension.
MedLine Citation:
PMID:  17909120     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hypertension in normal-weight and obese individuals is characterized by activation of the sympathetic nervous system. Measurement of spillover of the sympathetic transmitter, norepinephrine, to plasma indicates that the regional pattern of sympathetic activation in the 2 "variants" of essential hypertension differs, excluding the heart in obesity-related hypertension. Whether sympathetic nerve firing characteristics also differ is unknown. We studied multiunit and single fiber sympathetic nerve firing properties in patients with normal-weight hypertension and obesity-related hypertension, comparing these with nerve characteristics in normal-weight and obese people with normal blood pressure. Both normal-weight hypertensive (n=10) and obese hypertensive (n=14) patients had increased total multiunit muscle sympathetic nerve activity compared with the normal-weight (n=11) and obese (n=11) people with normal blood pressure (65+/-4 versus 47+/-6 bursts per 100 heartbeats, P<0.01 in the normal-weight groups and 68+/-4 versus 53+/-3 bursts per 100 beats, P<0.01 in the obese groups). Sympathetic activation in normal-weight hypertension was characterized by increased firing rate of single vasoconstrictor fibers (70+/-8 versus 28+/-3 spikes per 100 beats; P<0.001), increased firing probability per heartbeat (39+/-3% versus 20+/-3%; P<0.001), and higher incidence of multiple spikes per heartbeat (30+/-4% versus 17+/-4%; P<0.05). Sympathetic activation in obesity-related hypertension differed, involving recruitment of previously silent fibers, which fired at a normal rate. The pattern of sympathetic activation in normal-weight and obesity-related hypertension differs in terms of both the firing characteristics of individual sympathetic fibers and the sympathetic outflows involved. The underlying central nervous system mechanism and the adverse consequences of the 2 modes of sympathetic activation may differ.
Authors:
Elisabeth Lambert; Nora Straznicky; Markus Schlaich; Murray Esler; Tye Dawood; Elodie Hotchkin; Gavin Lambert
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-10-01
Journal Detail:
Title:  Hypertension     Volume:  50     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-10-18     Completed Date:  2007-11-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  United States    
Other Details:
Languages:  eng     Pagination:  862-8     Citation Subset:  IM    
Affiliation:
Human Neurotransmitters Laboratory, Baker Heart Research Institute, Melbourne, Victoria, Australia. Elisabeth.lambert@baker.edu.au
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MeSH Terms
Descriptor/Qualifier:
Action Potentials
Adult
Aged
Blood Pressure
Electrocardiography
Electrophysiology
Female
Heart Rate
Humans
Hypertension / complications,  physiopathology*
Male
Microelectrodes
Middle Aged
Obesity / complications,  physiopathology*
Peroneal Nerve / physiopathology
Sympathetic Fibers, Postganglionic / physiopathology
Sympathetic Nervous System / physiopathology*
Thinness / physiopathology*
Comments/Corrections
Comment In:
Hypertension. 2007 Nov;50(5):835-6   [PMID:  17909119 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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