Histamine receptor blocking effects of cimetidine in the airways
| Autor: | H. Magnussen, Tahir Ahmed, Adam Wanner, William W Abraham, W. Oliver, V. Hartmann |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
medicine.medical_specialty
Allergy medicine.drug_class Immunology Respiratory System Pharmacology Toxicology Guanidines Histamine receptor chemistry.chemical_compound Internal medicine medicine Anticholinergic Animals Pharmacology (medical) Clemastine Drug Interactions Cimetidine Receptor Sheep Airway Resistance medicine.disease Endocrinology chemistry Histamine H2 Antagonists Injections Intravenous Bronchoconstriction Carbachol Female medicine.symptom Histamine medicine.drug |
| Zdroj: | Agents and actions. 13(1) |
| ISSN: | 0065-4299 |
| Popis: | We investigated the modification of histamine-induced bronchoconstriction by the H2-antagonist cimetidine in conscious sheep. One hundred breaths of 5% histamine aerosol increased mean (SD) pulmonary resistance (RL) by 5.6 (1.4) cmH2O/l/sec. This increase in RL was completely blocked by intravenous clemastine (0.5 mg), a specific H1-antagonist, indicating that the histamine-induced bronchoconstriction was mediated by H1-receptors. Intravenous cimetidine caused a dose-dependent enhancement of the histamine response between 1 and 1000 mg with a mean peak delta RL of 15.3 (5) cmH2O/l/sec (p less than 0.05) at the 1000 mg dose, while it blocked the histamine response at a dose of 2400 mg [delta RL = 1.9 (2) cmH2O/l/sec, p = NS]. This paradoxic effect was not related to an anticholinergic mechanism as intravenous cimetidine (2400 mg) failed to block carbachol-induced (25 breaths of 1% solution) bronchoconstriction. We conclude that in the ovine airway, cimetidine is a selective H2-histamine receptor blocker at lower tissue concentrations, and a combined H2- and H1-histamine receptor blocker at high tissue concentrations. |
| Databáze: | OpenAIRE |
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