Linked Life Data

15109213

Source:http://linkedlifedata.com/resource/pubmed/id/15109213

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-4-27
pubmed:abstractText
Focal recordings from individual postganglionic sympathetic neurones in awake human subjects have revealed common firing properties. One of the most striking features is that they tend to fire only once per sympathetic burst. Why this should be so is not known, but we propose that the short duration of the burst may limit the number of times a sympathetic neurone can fire. Indeed, while the normal variation in cardiac interval and burst duration is too narrow to reveal a correlation between burst duration and the number of spikes generated, we know that spike generation is doubled when burst duration is doubled following ectopic heart beats. To test the hypothesis that the burst duration constrains the firing of individual sympathetic neurones to one per burst, we used the human skeletomotor system as a model for the sympathetic nervous system, which allowed us to vary burst duration and amplitude experimentally. Intramuscular recordings were made from 27 single motor units (alpha motoneurones) in the tibialis anterior or soleus muscles of seven subjects; multiunit EMG activity was recorded via surface electrodes and blood pressure was recorded continuously. Subjects were instructed to generate EMG bursts of varying amplitude in the intervals between heart beats. By constraining the firing of alpha motoneurones to brief ( approximately 400 ms) bursts we could emulate real sympathetic bursts. Individual motoneurones generated 0-7 spikes during the emulated sympathetic bursts, with firing patterns similar to those exhibited by real sympathetic neurones. Eleven motor units showed significant positive linear correlations between the number of spikes they generated within a burst and its amplitude, whereas for 17 motor units there were significant positive correlations between the number of spikes and burst duration. This indicates that burst duration is a major determinant of the number of times an alpha motoneurone will fire during a brief burst, and we suggest that the same principle may explain the firing pattern typical of human sympathetic neurones.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0958-0670
pubmed:author
pubmed:issnType
Print
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
82-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Comparison of the firing patterns of human postganglionic sympathetic neurones and spinal alpha motoneurones during brief bursts.
pubmed:affiliation
Prince of Wales Medical Research Institute, University of New South Wales, Sydney, Australia. vg.macefield@unsw.edu.au
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't