Methacholine (chloride)

Methacholine (Acetyl-β-methylcholine) choride is a potent muscarinic-3 (M3) agonist. Methacholine choride acts directly on acetylcholine receptors on smooth muscle causing bronchoconstriction and airway narrowing. Methacholine choride shows a high sensitivity to identify bronchial hyperresponsiveness (BHR). Methacholine choride can be used to measure airway hyperresponsiveness (AHR) as a diagnostic aid in the assessment of individuals with asthma-like symptoms and normal resting expiratory flow rates[1][2][3][4].