bronchokonstriktive

Bronchokonstriktiva, or bronchoconstrictors, are substances that cause narrowing of the airways by constricting bronchial smooth muscle. They are the opposite of bronchodilators, which widen the airways. Bronchoconstriction can be triggered by endogenous mediators released during inflammatory or allergic responses, as well as by exogenous agents and environmental factors.

Mechanism of action involves stimulation of receptors on airway smooth muscle and surrounding tissues. Histamine and leukotrienes bind to receptors that promote muscle contraction and increased mucus production. Acetylcholine, released from parasympathetic nerves or administered as cholinergic agonists, induces contraction through muscarinic receptors. Prostaglandin F2alpha and other mediators also contribute to airway narrowing. In conditions such as allergic asthma, mast cell degranulation releases these mediators, and exposure to irritants, cold air, exercise, or pollen can provoke bronchoconstriction in susceptible individuals.

Examples include endogenous mediators such as histamine, leukotrienes C4, D4, and E4, and prostaglandin F2alpha. Pharmacologic bronchoconstrictors used in research and clinical testing include acetylcholine and its analogs like methacholine and carbachol, which provoke airway constriction to assess airway hyperresponsiveness. Environmental triggers such as smoke, air pollutants, and fine particulates can also provoke bronchoconstriction.

Clinical relevance lies in the role of bronchoconstriction in diseases such as asthma and anaphylaxis, where airway narrowing contributes to symptoms and can require management with bronchodilators and anti-inflammatory therapies. Methacholine challenge testing is an example of a controlled bronchoconstrictive response used to evaluate asthma.