Pharmacological characterization of effects of nifedipine on isolated guinea-pig and rat tracheal smooth muscle

J. B. Cheng, R. G. Townley

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Nifedipine, a relatively new Ca2+-channel blocking agent, has recently been shown to be effective in the treatment of exercise-induced asthma; however, the pharmacological mechanism by which it blocks bronchospasm is little understood. We have investigated and characterized its effects on the reactivity of isolated guinea-pig and rat tracheal smooth muscle. Although it (10-8-10-7 M) blocked the contraction of the rat tracheal muscle to KCl and CaCl2, nifedipine (10-7-10-6 M) did not significantly inhibit histamine, methacholine or serotonin-induced muscle contractions in guinea-pigs and the methacholine contraction in rats. Nifedipine produced a potent relaxation on contracted tracheal muscle. The concentration required to produce 50% relaxation of 10-5 M histamine-precontracted guinea-pig tracheal muscle was 8.31 ± 3.12 X 10-9 M, and the extent of the nifedipine-induced relaxation could be modified by the baseline and active contracted tension. Nifedipine was more potent in producing the relaxation in guinea-pig tracheal muscle than isoproterenol, theophylline or verapamil. However, the time required for 50% relaxation by 3 X 10-5 M isoproterenol was significantly less than the time for the nifedipine (3 X 10-5 M) or verapamil (10-4 M) effect. In addition, the Hill number of the nifedipine-induced relaxation was different from the value of the isoproterenol or verapamil effect. Our results indicate that nifedipine exerts a potent dilatory effect directly on airway muscle, and suggest that such effect could be one of its pharmacological actions on relieving bronchospasm.

Original languageEnglish
Pages (from-to)228-244
Number of pages17
JournalArchives Internationales de Pharmacodynamie et de Therapie
Volume263
Issue number2
StatePublished - 1983
Externally publishedYes

Fingerprint

Nifedipine
Smooth Muscle
Guinea Pigs
Pharmacology
Muscles
Verapamil
Isoproterenol
Bronchial Spasm
Methacholine Chloride
Histamine
Exercise-Induced Asthma
Theophylline
Muscle Contraction
Serotonin

All Science Journal Classification (ASJC) codes

  • Pharmacology

Cite this

Pharmacological characterization of effects of nifedipine on isolated guinea-pig and rat tracheal smooth muscle. / Cheng, J. B.; Townley, R. G.

In: Archives Internationales de Pharmacodynamie et de Therapie, Vol. 263, No. 2, 1983, p. 228-244.

Research output: Contribution to journalArticle

@article{53fa5c77f64044e6afc83cf636799836,
title = "Pharmacological characterization of effects of nifedipine on isolated guinea-pig and rat tracheal smooth muscle",
abstract = "Nifedipine, a relatively new Ca2+-channel blocking agent, has recently been shown to be effective in the treatment of exercise-induced asthma; however, the pharmacological mechanism by which it blocks bronchospasm is little understood. We have investigated and characterized its effects on the reactivity of isolated guinea-pig and rat tracheal smooth muscle. Although it (10-8-10-7 M) blocked the contraction of the rat tracheal muscle to KCl and CaCl2, nifedipine (10-7-10-6 M) did not significantly inhibit histamine, methacholine or serotonin-induced muscle contractions in guinea-pigs and the methacholine contraction in rats. Nifedipine produced a potent relaxation on contracted tracheal muscle. The concentration required to produce 50{\%} relaxation of 10-5 M histamine-precontracted guinea-pig tracheal muscle was 8.31 ± 3.12 X 10-9 M, and the extent of the nifedipine-induced relaxation could be modified by the baseline and active contracted tension. Nifedipine was more potent in producing the relaxation in guinea-pig tracheal muscle than isoproterenol, theophylline or verapamil. However, the time required for 50{\%} relaxation by 3 X 10-5 M isoproterenol was significantly less than the time for the nifedipine (3 X 10-5 M) or verapamil (10-4 M) effect. In addition, the Hill number of the nifedipine-induced relaxation was different from the value of the isoproterenol or verapamil effect. Our results indicate that nifedipine exerts a potent dilatory effect directly on airway muscle, and suggest that such effect could be one of its pharmacological actions on relieving bronchospasm.",
author = "Cheng, {J. B.} and Townley, {R. G.}",
year = "1983",
language = "English",
volume = "263",
pages = "228--244",
journal = "Archives Internationales de Pharmacodynamie et de Therapie",
issn = "0003-9780",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Pharmacological characterization of effects of nifedipine on isolated guinea-pig and rat tracheal smooth muscle

AU - Cheng, J. B.

AU - Townley, R. G.

PY - 1983

Y1 - 1983

N2 - Nifedipine, a relatively new Ca2+-channel blocking agent, has recently been shown to be effective in the treatment of exercise-induced asthma; however, the pharmacological mechanism by which it blocks bronchospasm is little understood. We have investigated and characterized its effects on the reactivity of isolated guinea-pig and rat tracheal smooth muscle. Although it (10-8-10-7 M) blocked the contraction of the rat tracheal muscle to KCl and CaCl2, nifedipine (10-7-10-6 M) did not significantly inhibit histamine, methacholine or serotonin-induced muscle contractions in guinea-pigs and the methacholine contraction in rats. Nifedipine produced a potent relaxation on contracted tracheal muscle. The concentration required to produce 50% relaxation of 10-5 M histamine-precontracted guinea-pig tracheal muscle was 8.31 ± 3.12 X 10-9 M, and the extent of the nifedipine-induced relaxation could be modified by the baseline and active contracted tension. Nifedipine was more potent in producing the relaxation in guinea-pig tracheal muscle than isoproterenol, theophylline or verapamil. However, the time required for 50% relaxation by 3 X 10-5 M isoproterenol was significantly less than the time for the nifedipine (3 X 10-5 M) or verapamil (10-4 M) effect. In addition, the Hill number of the nifedipine-induced relaxation was different from the value of the isoproterenol or verapamil effect. Our results indicate that nifedipine exerts a potent dilatory effect directly on airway muscle, and suggest that such effect could be one of its pharmacological actions on relieving bronchospasm.

AB - Nifedipine, a relatively new Ca2+-channel blocking agent, has recently been shown to be effective in the treatment of exercise-induced asthma; however, the pharmacological mechanism by which it blocks bronchospasm is little understood. We have investigated and characterized its effects on the reactivity of isolated guinea-pig and rat tracheal smooth muscle. Although it (10-8-10-7 M) blocked the contraction of the rat tracheal muscle to KCl and CaCl2, nifedipine (10-7-10-6 M) did not significantly inhibit histamine, methacholine or serotonin-induced muscle contractions in guinea-pigs and the methacholine contraction in rats. Nifedipine produced a potent relaxation on contracted tracheal muscle. The concentration required to produce 50% relaxation of 10-5 M histamine-precontracted guinea-pig tracheal muscle was 8.31 ± 3.12 X 10-9 M, and the extent of the nifedipine-induced relaxation could be modified by the baseline and active contracted tension. Nifedipine was more potent in producing the relaxation in guinea-pig tracheal muscle than isoproterenol, theophylline or verapamil. However, the time required for 50% relaxation by 3 X 10-5 M isoproterenol was significantly less than the time for the nifedipine (3 X 10-5 M) or verapamil (10-4 M) effect. In addition, the Hill number of the nifedipine-induced relaxation was different from the value of the isoproterenol or verapamil effect. Our results indicate that nifedipine exerts a potent dilatory effect directly on airway muscle, and suggest that such effect could be one of its pharmacological actions on relieving bronchospasm.

UR - http://www.scopus.com/inward/record.url?scp=0020612193&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0020612193&partnerID=8YFLogxK

M3 - Article

C2 - 6349566

AN - SCOPUS:0020612193

VL - 263

SP - 228

EP - 244

JO - Archives Internationales de Pharmacodynamie et de Therapie

JF - Archives Internationales de Pharmacodynamie et de Therapie

SN - 0003-9780

IS - 2

ER -