TY - JOUR
T1 - Antigen- and histamine H1 receptor-mediated relaxation of guinea pig isolated trachea
AU - Undem, Bradley J.
AU - Lichtenstein, Lawrence M.
AU - Adams, G. Kenneth
N1 - Funding Information:
The authors wish to thank Mrs. Sonya Meeker and Mrs. Kathy Rosewell for their skilled assistance in the laboratory. Dr. Elaine Alexander for assistance in histological studies and Mrs. Karen Nelson for assistance in preparing the manuscript. Supported by HL 30132 from the National Institutes of Health.
PY - 1987/7/23
Y1 - 1987/7/23
N2 - We have investigated the effect of challenge in vitro with specific antigen (ovalbumin) on actively sensitized guinea pig tracheal rings maximally precontracted with methacholine. Ovalbumin relaxed the trachea in a concentration-dependent fashion with a negative log ED50 value (g/ml) of 7.0 ± 0.3. In 16 experiments, the maximum antigen-induced relaxation was 26 ± 3% of complete relaxation induced by 10-3 M papaverine (x ± S.E.M.). Antigen-induced relaxations were selectively antagonized by diphenhydramine. Similarly, histamine relaxed the precontracted tracheal smooth muscle with a negative log molar ED50 of about 4.5 and a maximum effect of 28 ± 3% (x ± S.E.M., n = 20). Histamine-induced relaxations were antagonized by diphenhydramine and mepyramine but were unaffected by cimetidine, metiamide or burimamide. Dimaprit (10-5-10-3 M) did not relax the precontracted trachea. Indomethacin significantly inhibited relaxation induced by both antigen and histamine. In contrast, phenidone or 5,8,11,14-eicosatetraynoic acid had no effect on relaxation but reversed the inhibition by indomethacin. Neither propranolol (10-6 M) nor removing the tracheal epithelium inhibited histamine-induced relaxation. These results suggest that antigen-induced relaxation of guinea pig tracheal smooth muscle involves activation of histamine H1 receptors and can occur independently of arachidonic acid metabolism, β-adrenoceptor activation or airway epithelium.
AB - We have investigated the effect of challenge in vitro with specific antigen (ovalbumin) on actively sensitized guinea pig tracheal rings maximally precontracted with methacholine. Ovalbumin relaxed the trachea in a concentration-dependent fashion with a negative log ED50 value (g/ml) of 7.0 ± 0.3. In 16 experiments, the maximum antigen-induced relaxation was 26 ± 3% of complete relaxation induced by 10-3 M papaverine (x ± S.E.M.). Antigen-induced relaxations were selectively antagonized by diphenhydramine. Similarly, histamine relaxed the precontracted tracheal smooth muscle with a negative log molar ED50 of about 4.5 and a maximum effect of 28 ± 3% (x ± S.E.M., n = 20). Histamine-induced relaxations were antagonized by diphenhydramine and mepyramine but were unaffected by cimetidine, metiamide or burimamide. Dimaprit (10-5-10-3 M) did not relax the precontracted trachea. Indomethacin significantly inhibited relaxation induced by both antigen and histamine. In contrast, phenidone or 5,8,11,14-eicosatetraynoic acid had no effect on relaxation but reversed the inhibition by indomethacin. Neither propranolol (10-6 M) nor removing the tracheal epithelium inhibited histamine-induced relaxation. These results suggest that antigen-induced relaxation of guinea pig tracheal smooth muscle involves activation of histamine H1 receptors and can occur independently of arachidonic acid metabolism, β-adrenoceptor activation or airway epithelium.
KW - (Immediate hypersensitivity)
KW - Anaphylaxis
KW - Antigen-induced contraction
KW - Histamine
KW - Histamine antagonists
KW - Smooth muscle (airway)
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U2 - 10.1016/0014-2999(87)90587-5
DO - 10.1016/0014-2999(87)90587-5
M3 - Article
C2 - 3117573
AN - SCOPUS:0023525808
VL - 139
SP - 297
EP - 305
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
SN - 0014-2999
IS - 3
ER -