Contraction of guinea-pig lung parenchymal strips by substance P and related peptides.
A dose-response relationship for substance P and contraction of the lung parenchyma strip of the guinea-pig could only be obtained in the presence of a mixture of bacitracin, 1,4 dithio-L-threitol and ethylenediamine tetracetic acid, all at 100 microM, or in the presence of captopril, 1.8 mM. Substance P (50 nM) caused no contraction by itself but produced a shift to the left of the dose-response curve for histamine with a mean dose-ratio of 1.4 +/- 0.2 (S.E. of mean). The peptides physalaemin, eledoisin and kassinin were all approximately equipotent with substance P on the lung strip, in the presence of peptides inhibitors. [D-Pro4, D-Trp7,9,10]-SP4-11, produced dose-related inhibition of the contraction induced by substance P. Substance P activity in guinea-pig lung declined exponentially with a half-time of 2.3 min: bacitracin, dithiothreitol and EDTA (all 100 microM) increased this to 7.2 min and captopril (1.8 mM) to 5.1 min.
J C
JC
Foreman
R
R
Shelly
S E
SE
Webber
D000818:Animals; D001414:Bacitracin / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology; D002744:Chlorpheniramine / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004600:Eledoisin / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D015286:Kassinin; D008168:Lung / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D010803:Physalaemin / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D013373:Substance P / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D009842:Oligopeptides; D010446:Peptide Fragments; D010455:Peptides; D011480:Protease Inhibitors; D001414:Bacitracin; D010803:Physalaemin; D013373:Substance P; D002744:Chlorpheniramine; D015286:Kassinin; D004600:Eledoisin; C045505:substance P (4-11), Pro(4)-Trp(7,9)-; D006632:Histamine; D004492:Edetic Acid; D002216:Captopril; D004229:Dithiothreitol