Adenosine-induced bronchoconstriction in conscious hyperresponsive and sensitized guinea pigs

Area of Science:

• * Respiratory Physiology
• * Pharmacology
• * Immunology

Background:

• * Inhaled adenosine induces bronchoconstriction in asthmatic subjects.
• * Airway hyperresponsiveness is a hallmark of asthma.
• * Ozone and platelet-activating factor (PAF) are known airway irritants.

Purpose of the Study:

• * To investigate the effects of inhaled adenosine in a guinea pig model of allergic sensitization and airway hyperresponsiveness.
• * To determine the impact of ozone and PAF exposure on airway responses to carbachol and adenosine.

Main Methods:

• * Conscious guinea pigs were sensitized with ovalbumin.
• * Airway hyperresponsiveness was induced by exposure to ozone or PAF.
• * Airway responses were measured using whole-body plethysmography to assess specific airway conductance (SGaw).

Main Results:

• * Ovalbumin-sensitized guinea pigs showed bronchoconstriction in response to adenosine.
• * PAF and ozone exposure induced significant airway hyperresponsiveness to carbachol.
• * Adenosine administration did not cause bronchoconstriction in untreated control animals.

Conclusions:

• * Adenosine can induce bronchoconstriction in sensitized airways.
• * Ozone and PAF are effective in creating a model of airway hyperresponsiveness in guinea pigs.
• * This model can be used to study mechanisms of airway hyperresponsiveness and potential therapeutic interventions.