Final answer:
A mutation in the G-protein's alpha subunit preventing GTP hydrolysis would result in a more severe allergic response due to prolonged activation of the histamine signaling pathway. Antihistamines work to block histamine receptors, treating pruritus and other allergic symptoms. Mast cells release histamine during allergic reactions, leading to symptoms such as itching, swelling, and redness.
Step-by-step explanation:
When histamine binds to the H1 G-protein-linked receptor, it initiates symptoms associated with an allergic reaction such as itchiness (pruritus) and airway constriction. If a mutation occurred in the G-protein's alpha subunit that prevented the hydrolysis of GTP, the allergic response would likely be more severe. This is because the G-protein would remain active for a longer period, continuously signaling and amplifying the cellular response leading to enhanced pruritus histamine effects.
Antihistamines are medications that work by blocking histamine receptors, with H1-antihistamines targeting the histamine H1 receptors, and H2-antihistamines binding to histamine H2 receptors. These drugs are used to treat the various symptoms caused by the release of histamine such as itching, swelling, and redness - a reaction often seen when mast cells release histamine into tissues during an allergic response.