Linked Life Data

9094728

Source:http://linkedlifedata.com/resource/pubmed/id/9094728

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1997-6-9
pubmed:abstractText
We studied the effects of recurrent aspiration of milk on neural control of airways in young developing rabbits. Beginning at 1 week of age, rabbits received 0.5 ml/kg of whole milk or sterile physiologic saline intranasally while under light methoxyflourane anesthesia 5 days a week for a period of 3 weeks. At 4 and 8 weeks of age, in vitro studies of contractile and relaxant responses of tracheal smooth muscle (TSM) segments were evaluated. To assess the neurally mediated contractile responses, frequency response curves to electrical field stimulation (EFS) were performed with results expressed in terms of frequency of EFS causing 50% of the maximal contractile response (ES50) values. In addition, the contractile responsiveness of TSM to methacholine (MCh) as reflected by the concentration causing 50% of the maximal contractile response (EC50) values was also determined to evaluate the underlying cholinergic reactivity of this segment of airway. To assess nonadrenergic noncholinergic inhibitory (NANCi) responses, experiments were performed on TSM contracted with neurokinin A in the presence of atropine, propranolol, and indomethacin. EFS was delivered to the contracted tissue at stimulation frequencies ranging from 5 to 30 Hz with results expressed as mean percent relaxation. Recurrent aspiration of milk but not saline increased EFS-induced contractile responses, as shown by significantly lower ES50 values compared with the control group: P = 0.02 and P = 0.001 at 4 and 8 weeks of age, respectively. TSM responsiveness to MCh was no different between the two groups, suggesting that alterations in prejunctional mechanisms of neural control were most likely responsible for the increased contractile response to EFS. The NANCi responses were significantly decreased by milk aspiration at both 4 and 8 weeks of age, with the abnormalities less pronounced at the later time point. These findings demonstrate that repeated aspiration of milk leads to abnormal mechanisms of neural control within airways of developing rabbits. While aspiration of milk altered both contractile and relaxant responses to EFS, the former abnormalities became more pronounced with time while the latter appeared to be resolving. These observations suggest that injury to an airway early in development does not necessarily resolve with time but may persist, with functional abnormalities becoming more pronounced even after the airway insult has ceased.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
8755-6863
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
198-204
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Effect of aspiration of milk on mechanisms of neural control in the airways of developing rabbits.
pubmed:affiliation
Division of Pediatric Pulmonary Medicine, National Jewish Center for Immunology and Respiratory Medicine, University of Colorado School of Medicine, Denver, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.