What occurs when Beta 2 receptors are blocked in the airways?

When β2 adrenergic receptors in the airways are blocked, bronchoconstriction occurs. β2 receptors are primarily responsible for mediating bronchodilation; they are stimulated by catecholamines, which lead to relaxation of smooth muscle in the bronchial passages. Therefore, when these receptors are antagonized or blocked, the result is a reduction in this relaxing effect, causing the bronchial smooth muscles to constrict.

This reaction can lead to narrower airways, making it more difficult for air to flow in and out of the lungs, thus worsening conditions like asthma or COPD. The other options, such as vasodilation and increased mucus production, are not directly influenced by the blockage of β2 receptors in the same way. These responses may involve different receptor types or mechanisms that are unrelated to the primary function of β2 receptors in the airways.