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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2002-1-25
pubmed:abstractText
The excitatory responses of deflationary slowly adapting pulmonary stretch receptor (SAR) activity to lung deflation ranging from approximately -15 to -25 cm of H(2)O for approximately 5 s were examined before and after administration of flecainide, a Na(+) channel blocker, and K(+) channel blockers, such as 4-aminopyridine (4-AP) and tetraethylammonium (TEA). The experiments were performed in anesthetized, artificially ventilated rats after unilateral vagotomy. The deflationary SARs increased their activity during lung deflation and its effect became more pronounced by increasing the degree of negative pressure. During lung deflation the average values for the deflationary SAR adaptation index (AI) were below 40%. Intravenous administration of veratridine (50 microg/kg), an Na(+) channel opener, stimulated deflationary SAR activity: one maintained excitatory activity mainly during deflation and the other receptors showed a tonic discharge during both deflation and inflation. Despite the difference in deflationary SAR firing patterns after veratridine administration, flecainide treatment (6.0 mg/kg) blocked veratridine-induced deflationary SAR stimulation and also caused strong inhibition of the excitatory responses of deflationary SARs to lung deflation. Under these conditions, the average values for deflationary SAR AI were over 90%. The responses of deflationary SARs and deflationary SAR AI to lung deflation were not significantly altered by pretreatment with either 4-AP (0.7 and 2.0 mg/kg) or TEA (2.0 and 6.0 mg/kg). These results suggest that the excitatory effect of lung deflation on deflationary SAR activity is mediated by the activation of flecainide-sensitive Na(+) channels on the nerve terminals of deflationary SARs.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
300
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
597-604
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed-meshheading:11805222-4-Aminopyridine, pubmed-meshheading:11805222-Anesthesia, pubmed-meshheading:11805222-Animals, pubmed-meshheading:11805222-Anti-Arrhythmia Agents, pubmed-meshheading:11805222-Flecainide, pubmed-meshheading:11805222-Injections, Intravenous, pubmed-meshheading:11805222-Lung, pubmed-meshheading:11805222-Myelin Sheath, pubmed-meshheading:11805222-Nerve Fibers, Myelinated, pubmed-meshheading:11805222-Potassium Channel Blockers, pubmed-meshheading:11805222-Potassium Channels, pubmed-meshheading:11805222-Pulmonary Stretch Receptors, pubmed-meshheading:11805222-Rats, pubmed-meshheading:11805222-Rats, Wistar, pubmed-meshheading:11805222-Respiration, Artificial, pubmed-meshheading:11805222-Sciatic Nerve, pubmed-meshheading:11805222-Tetraethylammonium, pubmed-meshheading:11805222-Vagotomy, pubmed-meshheading:11805222-Veratridine
pubmed:year
2002
pubmed:articleTitle
Excitatory mechanism of deflationary slowly adapting pulmonary stretch receptors in the rat lung.
pubmed:affiliation
Department of Physiology, Nippon Dental University, School of Dentistry at Tokyo, Tokyo, Japan. matsu-s@tky.ndu.ac.jp
pubmed:publicationType
Journal Article