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Effects of leukotriene D 4 on the mechanical and electrical properties of guinea‐pig isolated trachealis
Author(s) -
McCaig Dorothy J.,
Rodger I. W.
Publication year - 1988
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1988.tb11582.x
Subject(s) - trachealis muscle , guinea pig , leukotriene d4 , chemistry , biophysics , leukotriene , medicine , endocrinology , biology , biochemistry , membrane potential , charybdotoxin , asthma
1 The effects of leukotriene D 4 (LTD 4 ) on mechanical and electrical activity were examined in guinea‐pig isolated trachealis muscle and compared with two other bronchoconstrictors, methacholine and potassium chloride (KCl). 2 LTD 4 elicited concentration‐dependent increases in tension in trachealis muscle which were slower in time course than responses induced by either methacholine or KCl. The maximum response to LTD 4 was approximately 85% of the methacholine maximum. 3 At a concentration close to the EC 50 for tension changes, LTD 4 had no significant effect oneither transmembrane potential or slow wave activity recorded in single trachealis cells. 4 At a concentration close to the EC 90 for tension changes, LTD 4 caused significant membrane depolarization, transiently reduced the amplitude and increased the frequency of slow wave discharge and ultimately abolished slow wave discharge. LTD 4 ‐induced depolarization was less marked, and developed more slowly, than that evoked by either methacholine or KCl. 5 These results show that LTD 4 can elicit substantial increases in tension without altering transmembrane potential and are consistent with the view that LTD 4 initiates contraction mainly through potential‐independent mechanisms. However, at high concentrations the depolarization evoked by LTD 4 allows the possibility that potential‐dependent mechanisms may contribute to the spasm.