Effect of clenbuterol on histamine-induced airway obstruction in ponies.

This research examines the impacts of the drug clenbuterol on the airways of healthy ponies in response to histamine, revealing that it does not significantly alter base-line pulmonary function or protect against histamine-induced airway narrowing.

Study Design

In this study, beta 2-adrenergic receptor agonist clenbuterol was administered intravenously to twelve healthy ponies for the purpose of determining its effect on their pulmonary function, and their response to histamine.

• The dosage of clenbuterol given for each study was kept undisclosed to the investigators until they had finished analysing all gathered data, thereby ensuring the objectivity of tests and data interpretation.

Administration and Testing Methods

The dosage of clenbuterol given varied between 0.2, 0.8, and 1.6 micrograms/kg. In addition, tests were conducted at baseline, and after saline solution or clenbuterol had been administered.

• To create airway obstruction, an aerosol histamine was administered to the horses.
• Various measurements and observations were then made, including but not limited to arterial oxygen tension, dynamic compliance, and pulmonary resistance.

Correlation Between Clenbuterol Administration and Pulmonary Function

Despite varying the dosage, no significant alteration in the baseline pulmonary function was observed after the administration of clenbuterol.

• The aerosol histamine significantly impacted the ponies, decreasing arterial oxygen tension and dynamic compliance and increasing pulmonary resistance and minute ventilation.
• However, it did not affect arterial carbon dioxide tension and tidal volume.

Impacts of Clenbuterol on Histamine-Induced Airway Constriction

In the presence of each of the tested dosages of clenbuterol, the alterations caused by the aerosol histamine remained unchanged in magnitude.

• This implies that clenbuterol has no substantial protective effect against histamine-induced airway obstruction in healthy ponies.

Conclusions Drawn

Based on the findings of the study, it was concluded that the tested dosages of clenbuterol do not function as bronchodilators in healthy ponies, and also do not provide significant protection against airway narrowing induced by aerosol histamine.