Catecholamine and beta-adrenoceptor influences on airway reactivity to antigen in guinea pigs
| Autor: | Lavonne D. Meunier, R. R. Osborn, David C. Underwood, Linda B. Novak, Jane K. Matthews, Steven Bochnowicz |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Male
medicine.medical_specialty Ovalbumin medicine.medical_treatment Immunology Specific Airway Conductance Adrenergic beta-Antagonists Guinea Pigs Dose-Response Relationship Immunologic Propranolol Guinea pig Catecholamines Nadolol Internal medicine Receptors Adrenergic beta medicine Immunology and Allergy Animals business.industry Adrenalectomy General Medicine Plethysmography Endocrinology Epinephrine Injections Intravenous Catecholamine Bronchoconstriction medicine.symptom Bronchial Hyperreactivity business medicine.drug |
| Zdroj: | International archives of allergy and immunology. 109(3) |
| ISSN: | 1018-2438 |
| Popis: | The aim of the present study was to analyze the increased airway reactivity to antigen induced by beta-adrenoceptor blockade, adrenalectomy or medullectomy and to assess the contribution of circulating catecholamines to the increased reactivity. In anesthetized guinea pigs sensitized to ovalbumin (OA), administration of OA produced a dose-related bronchoconstriction characterized by threshold increases in airway insufflation pressure at 0.1 mg/kg i.v. and a near-maximal increase by 0.3 mg/kg i.v. Pretreatment with R(+) propranolol (0.5 mg/kg i.v.) 5 min prior to antigen did not significantly alter airway responses to antigen when compared to vehicle-treated animals. However, pretreatment with 0.5 mg/kg i.v. S(-) propranolol, racemic propranolol or nadolol markedly enhanced (10- to 15-fold) the airway response to the low-dose antigen. In addition, in guinea pigs which had been adrenalectomized, the reactivity to low-dose antigen was enhanced to a similar extent as that of beta-antagonist-treated animals when compared to sham-operated animals. Baseline plasma concentrations of epinephrine were significantly higher in sham-operate guinea pigs (1,494 +/- 223 ng/ml) when compared to adrenalectomized animals (412 +/- 44 ng/ml). Upon antigen exposure, epinephrine levels rose 5-fold (6,859 +/- 1,308 ng/ml) from baseline in sham-operated guinea pigs and were not significantly changed in adrenalectomized animals (848 +/- 208 ng/ml). Specific airway conductance measurements in conscious guinea pigs revealed that animals which had been medullectomized 2 weeks previously responded to lower provocative concentrations of aerosol OA (0.05-0.5%) than corresponding sham-operated animals. Airway reactivity to inhaled acetylcholine (0.1-1%) was similar in medullectomized and sham guinea pigs. Plasma concentrations of epinephrine were significantly lower in medullectomized guinea pigs (327 +/- 88 ng/ml) when compared to sham-operated animals (832 +/- 162 ng/ml). The results of the present study indicate that beta-adrenoceptor antagonism or changes in circulating epinephrine levels markedly alter the response to antigen in sensitized guinea pigs. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|